Dosing & Uses
Dosage Forms & Strengths
acetaminophen/doxylamine/phenylephrine
capsule
- 325mg/6.25mg/5mg
Sinus Pain, Congestion, Rhinorrhea, Sneezing, Headache
2 capsules PO q4hr; not to exceed 6 doses/day
Dosage Forms & Strengths
acetaminophen/doxylamine/phenylephrine
capsule
- 325mg/6.25mg/5mg
Sinus Pain, Congestion, Rhinorrhea, Sneezing, Headache
Vicks NyQuil Sinus
- <12 years: Ask a pediatrician
- ≥12 years: 2 capsules PO q4hr; not to exceed 6 doses/day
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Contraindicated (7)
- iobenguane I 123
phenylephrine decreases effects of iobenguane I 123 by receptor binding competition. Contraindicated. If clinically appropriate, discontinue drugs that compete for NE receptor sites for at least 5 half-lives; may cause false-negative imaging results.
- isocarboxazid
isocarboxazid increases effects of phenylephrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.
- linezolid
linezolid increases effects of phenylephrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.
- phenelzine
phenelzine increases effects of phenylephrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.
- procarbazine
procarbazine increases effects of phenylephrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.
- selegiline transdermal
selegiline transdermal increases effects of phenylephrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.
- tranylcypromine
tranylcypromine increases effects of phenylephrine by pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.
Serious - Use Alternative (45)
- amitriptyline
amitriptyline, phenylephrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- amoxapine
amoxapine, phenylephrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- benzhydrocodone/acetaminophen
benzhydrocodone/acetaminophen, doxylamine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
- cabergoline
cabergoline, phenylephrine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.
- calcium/magnesium/potassium/sodium oxybates
doxylamine, calcium/magnesium/potassium/sodium oxybates. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
- clomipramine
clomipramine, phenylephrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- desflurane
desflurane increases toxicity of phenylephrine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.
desflurane increases levels of phenylephrine by decreasing metabolism. Contraindicated. - desipramine
desipramine, phenylephrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- dihydroergotamine
dihydroergotamine, phenylephrine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.
- dihydroergotamine intranasal
dihydroergotamine intranasal, phenylephrine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.
- doxapram
doxapram increases effects of phenylephrine by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive pressor effect.
- doxepin
doxepin, phenylephrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- ergoloid mesylates
ergoloid mesylates, phenylephrine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.
- ergotamine
ergotamine, phenylephrine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.
- ether
ether increases toxicity of phenylephrine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.
- etomidate
etomidate increases levels of phenylephrine by decreasing metabolism. Contraindicated.
- fentanyl
fentanyl, doxylamine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.
- fentanyl intranasal
fentanyl intranasal, doxylamine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.
- fentanyl transdermal
fentanyl transdermal, doxylamine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.
- fentanyl transmucosal
fentanyl transmucosal, doxylamine. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration with other CNS depressants, such as skeletal muscle relaxants, may cause respiratory depression, hypotension, profound sedation, coma, and/or death. Consider dose reduction of either or both agents to avoid serious adverse effects. Monitor for hypotension, respiratory depression, and profound sedation.
- hydrocodone
hydrocodone, doxylamine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
- imipramine
imipramine, phenylephrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- isocarboxazid
isocarboxazid increases effects of doxylamine by Other (see comment). Avoid or Use Alternate Drug. Comment: Isocarboxazid should not be administered in combination with antihistamines because of potential additive CNS depressant effects. MAO inhibitors also prolong and intensify anticholinergic effects of antihistamines. .
- isoflurane
isoflurane increases toxicity of phenylephrine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.
- lemborexant
lemborexant, doxylamine. Either increases effects of the other by sedation. Avoid or Use Alternate Drug. Use of lemborexant with other drugs to treat insomnia is not recommended.
- lofepramine
lofepramine, phenylephrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- maprotiline
maprotiline, phenylephrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- methoxyflurane
methoxyflurane increases toxicity of phenylephrine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.
- methylene blue
methylene blue and doxylamine both increase serotonin levels. Avoid or Use Alternate Drug. If drug combination must be administered, monitor for evidence of serotonergic or opioid-related toxicities
- methylergonovine
methylergonovine, phenylephrine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.
- metoclopramide intranasal
doxylamine, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.
- nortriptyline
nortriptyline, phenylephrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- olopatadine intranasal
doxylamine and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.
- propofol
propofol increases levels of phenylephrine by decreasing metabolism. Contraindicated.
- protriptyline
protriptyline, phenylephrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- selinexor
selinexor, doxylamine. unspecified interaction mechanism. Avoid or Use Alternate Drug. Patients treated with selinexor may experience neurological toxicities. Avoid taking selinexor with other medications that may cause dizziness or confusion.
- sevoflurane
sevoflurane increases toxicity of phenylephrine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.
sevoflurane increases levels of phenylephrine by decreasing metabolism. Contraindicated. - sodium oxybate
doxylamine, sodium oxybate. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
- sufentanil SL
sufentanil SL, doxylamine. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration may result in hypotension, profound sedation, respiratory depression, coma, and death. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
- tranylcypromine
tranylcypromine increases effects of doxylamine by Other (see comment). Avoid or Use Alternate Drug. Comment: Tranylcypromine should not be administered in combination with antihistamines because of potential additive CNS depressant effects. MAO inhibitors also prolong and intensify anticholinergic effects of antihistamines. .
- trazodone
trazodone, phenylephrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- trimipramine
trimipramine, phenylephrine. Other (see comment). Avoid or Use Alternate Drug. Comment: Tricyclic antidepressants increase or decrease effects of sympathomimetics, by blocking reuptake of NE, or blocking uptake of indirect sympathomimetics into the adrenergic neuron.
- valerian
valerian and doxylamine both increase sedation. Avoid or Use Alternate Drug.
- yohimbe
yohimbe, phenylephrine. Mechanism: pharmacodynamic synergism. Contraindicated. Risk of acute hypertensive episode.
- zuranolone
doxylamine, zuranolone. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Coadministration of zuranolone with other CNS depressants may increase impairment of psychomotor performance or CNS depressant effects. If unavoidable, consider dose reduction. .
Monitor Closely (273)
- abobotulinumtoxinA
doxylamine increases effects of abobotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Drugs with anticholinergic effects may potentiate botulinum toxin effects, which may result in excessive neuromuscular weakness and heighten systemic anticholinergic effects.
- acrivastine
acrivastine and doxylamine both increase sedation. Use Caution/Monitor.
- albuterol
albuterol and phenylephrine both decrease sedation. Use Caution/Monitor.
albuterol and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - alfentanil
doxylamine and alfentanil both increase sedation. Use Caution/Monitor.
alfentanil increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - alprazolam
alprazolam and doxylamine both increase sedation. Use Caution/Monitor.
alprazolam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - amifampridine
doxylamine increases toxicity of amifampridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Amifampridine can cause seizures. Coadministration with drugs that lower seizure threshold may increase this risk.
- amitriptyline
amitriptyline increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- amisulpride
amisulpride and doxylamine both increase sedation. Use Caution/Monitor.
- amitriptyline
doxylamine and amitriptyline both increase sedation. Use Caution/Monitor.
- amobarbital
amobarbital increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
amobarbital and doxylamine both increase sedation. Use Caution/Monitor. - amoxapine
amoxapine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and amoxapine both increase sedation. Use Caution/Monitor. - amphetamine
amphetamine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.
amphetamine and phenylephrine both decrease sedation. Use Caution/Monitor.
doxylamine increases and amphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - apomorphine
doxylamine and apomorphine both increase sedation. Use Caution/Monitor.
- arformoterol
arformoterol and phenylephrine both decrease sedation. Use Caution/Monitor.
arformoterol and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - aripiprazole
aripiprazole increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and aripiprazole both increase sedation. Use Caution/Monitor. - armodafinil
armodafinil and phenylephrine both decrease sedation. Use Caution/Monitor.
- asenapine
asenapine and doxylamine both increase sedation. Use Caution/Monitor.
- asenapine transdermal
asenapine transdermal and doxylamine both increase sedation. Use Caution/Monitor.
- atomoxetine
atomoxetine, phenylephrine. Other (see comment). Use Caution/Monitor. Comment: Due to the potential for increases in blood pressure and heart rate, atomoxetine should be used cautiously with vasopressors such as phenylephrine.
- avapritinib
avapritinib and doxylamine both increase sedation. Use Caution/Monitor.
- azelastine
azelastine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
azelastine and doxylamine both increase sedation. Use Caution/Monitor. - baclofen
doxylamine and baclofen both increase sedation. Use Caution/Monitor.
- belladonna and opium
belladonna and opium increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- belladonna and opium
doxylamine and belladonna and opium both increase sedation. Use Caution/Monitor.
- benperidol
benperidol increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and benperidol both increase sedation. Use Caution/Monitor. - benzhydrocodone/acetaminophen
benzhydrocodone/acetaminophen and doxylamine both increase sedation. Use Caution/Monitor.
- benzphetamine
benzphetamine and phenylephrine both decrease sedation. Use Caution/Monitor.
benzphetamine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - benzphetamine
doxylamine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- brexanolone
brexanolone, doxylamine. Either increases toxicity of the other by sedation. Use Caution/Monitor.
- brexpiprazole
brexpiprazole and doxylamine both increase sedation. Use Caution/Monitor.
- brimonidine
brimonidine and doxylamine both increase sedation. Use Caution/Monitor.
- brivaracetam
brivaracetam and doxylamine both increase sedation. Use Caution/Monitor.
- bromocriptine
bromocriptine, phenylephrine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Hypertension, V tach.
- brompheniramine
brompheniramine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
brompheniramine and doxylamine both increase sedation. Use Caution/Monitor. - buprenorphine
doxylamine and buprenorphine both increase sedation. Use Caution/Monitor.
- buprenorphine buccal
buprenorphine buccal increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- buprenorphine buccal
doxylamine and buprenorphine buccal both increase sedation. Use Caution/Monitor.
- buprenorphine subdermal implant
buprenorphine subdermal implant and doxylamine both increase sedation. Use Caution/Monitor.
- buprenorphine transdermal
buprenorphine transdermal and doxylamine both increase sedation. Use Caution/Monitor.
- buprenorphine, long-acting injection
doxylamine increases toxicity of buprenorphine, long-acting injection by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of buprenorphine and benzodiazepines or other CNS depressants increases risk of adverse reactions including overdose, respiratory depression, and death. Cessation of benzodiazepines or other CNS depressants is preferred in most cases. In some cases, monitoring at a higher level of care for tapering CNS depressants may be appropriate. In others, gradually tapering a patient off of a prescribed benzodiazepine or other CNS depressant or decreasing to the lowest effective dose may be appropriate.
buprenorphine, long-acting injection and doxylamine both increase sedation. Use Caution/Monitor. - butabarbital
butabarbital and doxylamine both increase sedation. Use Caution/Monitor.
butabarbital increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - butalbital
butalbital and doxylamine both increase sedation. Use Caution/Monitor.
butalbital increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - butorphanol
butorphanol increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and butorphanol both increase sedation. Use Caution/Monitor. - caffeine
caffeine and phenylephrine both decrease sedation. Use Caution/Monitor.
- carbinoxamine
carbinoxamine and doxylamine both increase sedation. Use Caution/Monitor.
- carbinoxamine
carbinoxamine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- cariprazine
cariprazine and doxylamine both increase sedation. Use Caution/Monitor.
- carisoprodol
doxylamine and carisoprodol both increase sedation. Use Caution/Monitor.
- cenobamate
cenobamate, doxylamine. Either increases effects of the other by sedation. Use Caution/Monitor.
- chloral hydrate
chloral hydrate and doxylamine both increase sedation. Use Caution/Monitor.
chloral hydrate increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - chlordiazepoxide
chlordiazepoxide and doxylamine both increase sedation. Use Caution/Monitor.
chlordiazepoxide increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - chlorpheniramine
chlorpheniramine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
chlorpheniramine and doxylamine both increase sedation. Use Caution/Monitor. - chlorpromazine
doxylamine and chlorpromazine both increase sedation. Use Caution/Monitor.
chlorpromazine, phenylephrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
chlorpromazine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - chlorzoxazone
doxylamine and chlorzoxazone both increase sedation. Use Caution/Monitor.
- cinnarizine
cinnarizine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- cinnarizine
cinnarizine and doxylamine both increase sedation. Use Caution/Monitor.
- clemastine
clemastine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
clemastine and doxylamine both increase sedation. Use Caution/Monitor. - clobazam
doxylamine, clobazam. Other (see comment). Use Caution/Monitor. Comment: Concomitant administration can increase the potential for CNS effects (e.g., increased sedation or respiratory depression).
- clomipramine
clomipramine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- clomipramine
doxylamine and clomipramine both increase sedation. Use Caution/Monitor.
- clonazepam
clonazepam and doxylamine both increase sedation. Use Caution/Monitor.
clonazepam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - clonidine
clonidine, doxylamine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration enhances CNS depressant effects.
- clorazepate
clorazepate increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- clorazepate
clorazepate and doxylamine both increase sedation. Use Caution/Monitor.
- clozapine
clozapine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and clozapine both increase sedation. Use Caution/Monitor. - codeine
doxylamine and codeine both increase sedation. Use Caution/Monitor.
codeine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - cyclizine
cyclizine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
cyclizine and doxylamine both increase sedation. Use Caution/Monitor. - cyclobenzaprine
doxylamine and cyclobenzaprine both increase sedation. Use Caution/Monitor.
- cyproheptadine
cyproheptadine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- cyproheptadine
cyproheptadine and doxylamine both increase sedation. Use Caution/Monitor.
- dantrolene
doxylamine and dantrolene both increase sedation. Use Caution/Monitor.
- daridorexant
doxylamine and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.
- daxibotulinumtoxinA
doxylamine increases effects of daxibotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Drugs with anticholinergic effects may potentiate botulinum toxin effects, which may result in excessive neuromuscular weakness and heighten systemic anticholinergic effects.
- desipramine
doxylamine and desipramine both increase sedation. Use Caution/Monitor.
desipramine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - deutetrabenazine
doxylamine and deutetrabenazine both increase sedation. Use Caution/Monitor.
- dexchlorpheniramine
dexchlorpheniramine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- dexchlorpheniramine
dexchlorpheniramine and doxylamine both increase sedation. Use Caution/Monitor.
- dexfenfluramine
dexfenfluramine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.
doxylamine increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
dexfenfluramine and phenylephrine both decrease sedation. Use Caution/Monitor. - dexmedetomidine
dexmedetomidine and doxylamine both increase sedation. Use Caution/Monitor.
dexmedetomidine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - dexmethylphenidate
dexmethylphenidate and phenylephrine both decrease sedation. Use Caution/Monitor.
dexmethylphenidate and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - dextromoramide
doxylamine and dextromoramide both increase sedation. Use Caution/Monitor.
- dextroamphetamine
dextroamphetamine and phenylephrine both decrease sedation. Use Caution/Monitor.
dextroamphetamine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - dextromoramide
dextromoramide increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- diamorphine
doxylamine and diamorphine both increase sedation. Use Caution/Monitor.
diamorphine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - diazepam
diazepam and doxylamine both increase sedation. Use Caution/Monitor.
- diethylpropion
diethylpropion and phenylephrine both decrease sedation. Use Caution/Monitor.
diethylpropion and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - diazepam intranasal
diazepam intranasal, doxylamine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may potentiate the CNS-depressant effects of each drug.
- difelikefalin
difelikefalin and doxylamine both increase sedation. Use Caution/Monitor.
- difenoxin hcl
doxylamine and difenoxin hcl both increase sedation. Use Caution/Monitor.
difenoxin hcl increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - dimenhydrinate
dimenhydrinate increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
dimenhydrinate and doxylamine both increase sedation. Use Caution/Monitor. - diphenhydramine
diphenhydramine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
diphenhydramine and doxylamine both increase sedation. Use Caution/Monitor. - diphenoxylate hcl
diphenoxylate hcl increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and diphenoxylate hcl both increase sedation. Use Caution/Monitor. - dipipanone
doxylamine and dipipanone both increase sedation. Use Caution/Monitor.
dipipanone increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - dobutamine
dobutamine and phenylephrine both decrease sedation. Use Caution/Monitor.
dobutamine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - dopexamine
doxylamine increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- dopamine
dopamine and phenylephrine both decrease sedation. Use Caution/Monitor.
dopamine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - dopexamine
dopexamine and phenylephrine both decrease sedation. Use Caution/Monitor.
dopexamine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - dosulepin
doxylamine and dosulepin both increase sedation. Use Caution/Monitor.
- doxepin
doxepin increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and doxepin both increase sedation. Use Caution/Monitor. - droperidol
droperidol increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and droperidol both increase sedation. Use Caution/Monitor. - droxidopa
phenylephrine and droxidopa both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. May increase risk for supine hypertension
- esketamine intranasal
esketamine intranasal, doxylamine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.
- ephedrine
ephedrine and phenylephrine both decrease sedation. Use Caution/Monitor.
ephedrine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.
ephedrine, phenylephrine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. - epinephrine
epinephrine and phenylephrine both decrease sedation. Use Caution/Monitor.
epinephrine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - epinephrine inhaled
phenylephrine, epinephrine inhaled. Either increases effects of the other by sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.
- epinephrine racemic
epinephrine racemic and phenylephrine both decrease sedation. Use Caution/Monitor.
epinephrine racemic and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - estazolam
estazolam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
estazolam and doxylamine both increase sedation. Use Caution/Monitor. - ethanol
doxylamine and ethanol both increase sedation. Use Caution/Monitor.
ethanol increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - etomidate
etomidate and doxylamine both increase sedation. Use Caution/Monitor.
- fenfluramine
fenfluramine and phenylephrine both decrease sedation. Use Caution/Monitor.
fenfluramine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - fenfluramine
doxylamine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- fentanyl
fentanyl and doxylamine both increase sedation. Use Caution/Monitor.
- fentanyl intranasal
fentanyl intranasal and doxylamine both increase sedation. Use Caution/Monitor.
- fentanyl iontophoretic transdermal system
fentanyl iontophoretic transdermal system and doxylamine both increase sedation. Use Caution/Monitor.
- fentanyl transdermal
fentanyl transdermal and doxylamine both increase sedation. Use Caution/Monitor.
- fentanyl transmucosal
fentanyl transmucosal and doxylamine both increase sedation. Use Caution/Monitor.
- flibanserin
doxylamine and flibanserin both increase sedation. Modify Therapy/Monitor Closely. Risk for sedation increased if flibanserin is coadministration with other CNS depressants.
- fluphenazine
doxylamine and fluphenazine both increase sedation. Use Caution/Monitor.
fluphenazine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
fluphenazine, phenylephrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only. - flurazepam
flurazepam and doxylamine both increase sedation. Use Caution/Monitor.
flurazepam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - formoterol
formoterol and phenylephrine both decrease sedation. Use Caution/Monitor.
formoterol and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - gabapentin
gabapentin, doxylamine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.
- gabapentin enacarbil
gabapentin enacarbil, doxylamine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.
- ganaxolone
doxylamine and ganaxolone both increase sedation. Use Caution/Monitor.
- gotu kola
gotu kola increases effects of doxylamine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.
- haloperidol
haloperidol increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and haloperidol both increase sedation. Use Caution/Monitor. - hawthorn
hawthorn increases effects of doxylamine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.
- hydralazine
hydralazine, phenylephrine. Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Sympathomimetics can antagonize the activity of some antihypertensive agents.
- hops
hops increases effects of doxylamine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.
- hyaluronidase
doxylamine decreases effects of hyaluronidase by Other (see comment). Use Caution/Monitor. Comment: Antihistamines, when given in large systemic doses, may render tissues partially resistant to the action of hyaluronidase. Patients may require larger amounts of hyaluronidase for equivalent dispersing effect. .
- hydromorphone
doxylamine and hydromorphone both increase sedation. Use Caution/Monitor.
hydromorphone increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - hydroxyzine
hydroxyzine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
hydroxyzine and doxylamine both increase sedation. Use Caution/Monitor. - iloperidone
iloperidone increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and iloperidone both increase sedation. Use Caution/Monitor. - imipramine
imipramine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and imipramine both increase sedation. Use Caution/Monitor. - incobotulinumtoxinA
doxylamine increases effects of incobotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Drugs with anticholinergic effects may potentiate botulinum toxin effects, which may result in excessive neuromuscular weakness and heighten systemic anticholinergic effects.
- indacaterol, inhaled
phenylephrine increases effects of indacaterol, inhaled by Other (see comment). Use Caution/Monitor. Comment: If additional adrenergic drugs are to be administered by any route, they should be used with caution because the sympathetic effects of indacaterol may be potentiated.
- insulin degludec
phenylephrine decreases effects of insulin degludec by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Sympathomimetics increase blood glucose by stimulating alpha and beta receptors; this action results in increased hepatic glucose production, glycogenolysis, and decreased insulin secretion.
- insulin degludec/insulin aspart
phenylephrine decreases effects of insulin degludec/insulin aspart by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Sympathomimetics increase blood glucose by stimulating alpha and beta receptors; this action results in increased hepatic glucose production, glycogenolysis, and decreased insulin secretion.
- insulin inhaled
phenylephrine decreases effects of insulin inhaled by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. Sympathomimetics increase blood glucose by stimulating alpha and beta receptors; this action results in increased hepatic glucose production, glycogenolysis, and decreased insulin secretion.
- isoproterenol
isoproterenol and phenylephrine both decrease sedation. Use Caution/Monitor.
isoproterenol and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - kava
kava increases effects of doxylamine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.
- ketamine
ketamine and doxylamine both increase sedation. Use Caution/Monitor.
- ketotifen, ophthalmic
doxylamine and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.
ketotifen, ophthalmic increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - lasmiditan
lasmiditan, doxylamine. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.
- levalbuterol
levalbuterol and phenylephrine both decrease sedation. Use Caution/Monitor.
levalbuterol and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - letibotulinumtoxinA
doxylamine increases effects of letibotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Drugs with anticholinergic effects may potentiate botulinum toxin effects, which may result in excessive neuromuscular weakness and heighten systemic anticholinergic effects.
- levetiracetam
levetiracetam and doxylamine both increase sedation. Use Caution/Monitor.
- levorphanol
levorphanol increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and levorphanol both increase sedation. Use Caution/Monitor. - lisdexamfetamine
lisdexamfetamine and phenylephrine both decrease sedation. Use Caution/Monitor.
lisdexamfetamine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - lofepramine
doxylamine and lofepramine both increase sedation. Use Caution/Monitor.
- lofepramine
lofepramine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- lofexidine
lofexidine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and lofexidine both increase sedation. Use Caution/Monitor. - loprazolam
loprazolam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
loprazolam and doxylamine both increase sedation. Use Caution/Monitor. - lorazepam
lorazepam and doxylamine both increase sedation. Use Caution/Monitor.
lorazepam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - lormetazepam
lormetazepam and doxylamine both increase sedation. Use Caution/Monitor.
lormetazepam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - loxapine
doxylamine and loxapine both increase sedation. Use Caution/Monitor.
loxapine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - loxapine inhaled
loxapine inhaled increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and loxapine inhaled both increase sedation. Use Caution/Monitor. - lurasidone
lurasidone, doxylamine. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.
- maprotiline
maprotiline increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- maprotiline
doxylamine and maprotiline both increase sedation. Use Caution/Monitor.
- marijuana
doxylamine and marijuana both increase sedation. Use Caution/Monitor.
marijuana increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - melatonin
doxylamine and melatonin both increase sedation. Use Caution/Monitor.
melatonin increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - meperidine
meperidine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and meperidine both increase sedation. Use Caution/Monitor. - meprobamate
meprobamate increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and meprobamate both increase sedation. Use Caution/Monitor. - metaproterenol
metaproterenol and phenylephrine both decrease sedation. Use Caution/Monitor.
metaproterenol and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - metaxalone
doxylamine and metaxalone both increase sedation. Use Caution/Monitor.
- methadone
doxylamine and methadone both increase sedation. Use Caution/Monitor.
methadone increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - methamphetamine
methamphetamine and phenylephrine both decrease sedation. Use Caution/Monitor.
methamphetamine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - methocarbamol
doxylamine and methocarbamol both increase sedation. Use Caution/Monitor.
- methohexital
methohexital and doxylamine both increase sedation. Use Caution/Monitor.
- methyldopa
methyldopa increases effects of phenylephrine by unknown mechanism. Use Caution/Monitor.
- methylenedioxymethamphetamine
methylenedioxymethamphetamine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.
doxylamine increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
methylenedioxymethamphetamine and phenylephrine both decrease sedation. Use Caution/Monitor. - midazolam
midazolam and doxylamine both increase sedation. Use Caution/Monitor.
midazolam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - midazolam intranasal
midazolam intranasal, doxylamine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.
- midodrine
midodrine and phenylephrine both decrease sedation. Use Caution/Monitor.
midodrine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - mirtazapine
doxylamine and mirtazapine both increase sedation. Use Caution/Monitor.
mirtazapine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - modafinil
modafinil and phenylephrine both decrease sedation. Use Caution/Monitor.
- morphine
doxylamine and morphine both increase sedation. Use Caution/Monitor.
- morphine
morphine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- motherwort
doxylamine and motherwort both increase sedation. Use Caution/Monitor.
motherwort increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - moxonidine
moxonidine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and moxonidine both increase sedation. Use Caution/Monitor. - nabilone
nabilone increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and nabilone both increase sedation. Use Caution/Monitor. - nadolol
nadolol increases effects of phenylephrine by pharmacodynamic synergism. Use Caution/Monitor. Risk of acute hypertensive episode (rare).
- nalbuphine
doxylamine and nalbuphine both increase sedation. Use Caution/Monitor.
- nalbuphine
nalbuphine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- norepinephrine
norepinephrine and phenylephrine both decrease sedation. Use Caution/Monitor.
norepinephrine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - nortriptyline
nortriptyline increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and nortriptyline both increase sedation. Use Caution/Monitor. - olanzapine
olanzapine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and olanzapine both increase sedation. Use Caution/Monitor. - olanzapine/samidorphan
doxylamine, olanzapine/samidorphan. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration of diazepam, alcohol, or other CNS acting drugs may potentiate orthostatic hypotension observed with olanzapine. Additive sedation may also occur.
- olodaterol inhaled
phenylephrine and olodaterol inhaled both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. Caution with coadministration of adrenergic drugs by any route because of additive sympathetic effects
- oliceridine
oliceridine, doxylamine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.
- onabotulinumtoxinA
doxylamine increases effects of onabotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Drugs with anticholinergic effects may potentiate botulinum toxin effects, which may result in excessive neuromuscular weakness and heighten systemic anticholinergic effects.
- opium tincture
doxylamine and opium tincture both increase sedation. Use Caution/Monitor.
opium tincture increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - orphenadrine
doxylamine and orphenadrine both increase sedation. Use Caution/Monitor.
- oxazepam
oxazepam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- oxazepam
oxazepam and doxylamine both increase sedation. Use Caution/Monitor.
- oxycodone
doxylamine and oxycodone both increase sedation. Use Caution/Monitor.
oxycodone increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - oxymetazoline topical
oxymetazoline topical and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.
- oxymorphone
doxylamine and oxymorphone both increase sedation. Use Caution/Monitor.
- oxymorphone
oxymorphone increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- oxytocin
oxytocin increases effects of phenylephrine by pharmacodynamic synergism. Use Caution/Monitor.
- paliperidone
doxylamine and paliperidone both increase sedation. Use Caution/Monitor.
paliperidone increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - papaveretum
papaveretum increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and papaveretum both increase sedation. Use Caution/Monitor. - papaverine
doxylamine and papaverine both increase sedation. Use Caution/Monitor.
- pentazocine
pentazocine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- passion flower
passion flower increases effects of doxylamine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.
- pentazocine
doxylamine and pentazocine both increase sedation. Use Caution/Monitor.
- pentobarbital
pentobarbital and doxylamine both increase sedation. Use Caution/Monitor.
pentobarbital increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - perphenazine
perphenazine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
perphenazine, phenylephrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
doxylamine and perphenazine both increase sedation. Use Caution/Monitor. - phendimetrazine
phendimetrazine and phenylephrine both decrease sedation. Use Caution/Monitor.
phendimetrazine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - phenelzine
phenelzine increases effects of doxylamine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Coadministration of phenelzine and antihistamines may result in additive CNS depressant effects. MAO inhibitors also prolong and intensify anticholinergic effects of antihistamines. .
- phenobarbital
phenobarbital and doxylamine both increase sedation. Use Caution/Monitor.
phenobarbital increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - phentermine
phentermine and phenylephrine both decrease sedation. Use Caution/Monitor.
phentermine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - phenylephrine PO
doxylamine increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .
- pholcodine
doxylamine and pholcodine both increase sedation. Use Caution/Monitor.
pholcodine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - pimozide
pimozide increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and pimozide both increase sedation. Use Caution/Monitor. - pindolol
pindolol increases effects of phenylephrine by pharmacodynamic synergism. Use Caution/Monitor. Risk of acute hypertensive episode (rare).
- prabotulinumtoxinA
doxylamine increases effects of prabotulinumtoxinA by pharmacodynamic synergism. Use Caution/Monitor. Drugs with anticholinergic effects may potentiate botulinum toxin effects, which may result in excessive neuromuscular weakness and heighten systemic anticholinergic effects.
- pirbuterol
pirbuterol and phenylephrine both decrease sedation. Use Caution/Monitor.
pirbuterol and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - pregabalin
pregabalin, doxylamine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of CNS depressants can result in serious, life-threatening, and fatal respiratory depression. Use lowest dose possible and monitor for respiratory depression and sedation.
- primidone
primidone and doxylamine both increase sedation. Use Caution/Monitor.
primidone increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - prochlorperazine
doxylamine and prochlorperazine both increase sedation. Use Caution/Monitor.
prochlorperazine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
prochlorperazine, phenylephrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only. - promazine
promazine, phenylephrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only.
- promethazine
promethazine and doxylamine both increase sedation. Use Caution/Monitor.
- promethazine
promethazine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
promethazine, phenylephrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only. - propofol
propofol increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
propofol and doxylamine both increase sedation. Use Caution/Monitor. - propranolol
propranolol increases effects of phenylephrine by pharmacodynamic synergism. Use Caution/Monitor. Risk of acute hypertensive episode (rare).
- propylhexedrine
doxylamine increases and propylhexedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- propylhexedrine
phenylephrine and propylhexedrine both decrease sedation. Use Caution/Monitor.
phenylephrine and propylhexedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - protriptyline
doxylamine and protriptyline both increase sedation. Use Caution/Monitor.
protriptyline increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - pseudoephedrine
phenylephrine and pseudoephedrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.
- quazepam
quazepam and doxylamine both increase sedation. Use Caution/Monitor.
- quazepam
quazepam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- quetiapine
quetiapine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and quetiapine both increase sedation. Use Caution/Monitor. - ramelteon
doxylamine and ramelteon both increase sedation. Use Caution/Monitor.
- rasagiline
rasagiline increases effects of phenylephrine by pharmacodynamic synergism. Use Caution/Monitor. Risk of acute hypertensive episode.
- remimazolam
remimazolam, doxylamine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely. Coadministration may result in profound sedation, respiratory depression, coma, and/or death. Continuously monitor vital signs during sedation and recovery period if coadministered. Carefully titrate remimazolam dose if administered with opioid analgesics and/or sedative/hypnotics.
- rimabotulinumtoxinB
doxylamine increases effects of rimabotulinumtoxinB by pharmacodynamic synergism. Use Caution/Monitor. Drugs with anticholinergic effects may potentiate botulinum toxin effects, which may result in excessive neuromuscular weakness and heighten systemic anticholinergic effects.
- risperidone
risperidone increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and risperidone both increase sedation. Use Caution/Monitor. - safinamide
phenylephrine and safinamide both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. Monitor patients for hypertension if safinamide is prescribed concomitantly with prescription or nonprescription sympathomimetics, including nasal, oral, or ophthalmic decongestants and cold remedies.
- scullcap
doxylamine and scullcap both increase sedation. Use Caution/Monitor.
- salmeterol
salmeterol and phenylephrine both decrease sedation. Use Caution/Monitor.
salmeterol and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - scullcap
scullcap increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- secobarbital
secobarbital increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
secobarbital and doxylamine both increase sedation. Use Caution/Monitor. - selegiline
selegiline increases effects of phenylephrine by pharmacodynamic synergism. Use Caution/Monitor. Risk of acute hypertensive episode.
- sevoflurane
sevoflurane and doxylamine both increase sedation. Use Caution/Monitor.
- serdexmethylphenidate/dexmethylphenidate
serdexmethylphenidate/dexmethylphenidate and phenylephrine both decrease sedation. Use Caution/Monitor.
serdexmethylphenidate/dexmethylphenidate and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - shepherd's purse
doxylamine and shepherd's purse both increase sedation. Use Caution/Monitor.
shepherd's purse increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - solriamfetol
phenylephrine and solriamfetol both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.
- stiripentol
stiripentol, doxylamine. Either increases effects of the other by sedation. Use Caution/Monitor. Concomitant use stiripentol with other CNS depressants, including alcohol, may increase the risk of sedation and somnolence.
- sufentanil
sufentanil increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and sufentanil both increase sedation. Use Caution/Monitor. - tapentadol
tapentadol increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and tapentadol both increase sedation. Use Caution/Monitor. - temazepam
temazepam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
temazepam and doxylamine both increase sedation. Use Caution/Monitor. - terbutaline
terbutaline and phenylephrine both decrease sedation. Use Caution/Monitor.
terbutaline and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - thioridazine
doxylamine and thioridazine both increase sedation. Use Caution/Monitor.
- thioridazine
thioridazine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
thioridazine, phenylephrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only. - thiothixene
doxylamine and thiothixene both increase sedation. Use Caution/Monitor.
thiothixene increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - timolol
timolol increases effects of phenylephrine by pharmacodynamic synergism. Use Caution/Monitor. Risk of acute hypertensive episode (rare).
- topiramate
doxylamine and topiramate both increase sedation. Modify Therapy/Monitor Closely.
- topiramate
topiramate increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Modify Therapy/Monitor Closely.
- tramadol
doxylamine and tramadol both increase sedation. Use Caution/Monitor.
tramadol increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - trazodone
doxylamine and trazodone both increase sedation. Use Caution/Monitor.
trazodone increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - triazolam
triazolam and doxylamine both increase sedation. Use Caution/Monitor.
triazolam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - triclofos
doxylamine and triclofos both increase sedation. Use Caution/Monitor.
triclofos increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - trifluoperazine
doxylamine and trifluoperazine both increase sedation. Use Caution/Monitor.
trifluoperazine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
trifluoperazine, phenylephrine. Mechanism: unknown. Use Caution/Monitor. Risk of cardiac arrhythmia or sudden death, more likely w/thioridazine than other phenothiazines. Interaction more likely in certain predisposed pts. only. - trimipramine
trimipramine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and trimipramine both increase sedation. Use Caution/Monitor. - triprolidine
triprolidine and doxylamine both increase sedation. Use Caution/Monitor.
triprolidine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. - valerian
valerian increases effects of doxylamine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.
- xylometazoline
phenylephrine and xylometazoline both decrease sedation. Use Caution/Monitor.
phenylephrine and xylometazoline both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - xylometazoline
doxylamine increases and xylometazoline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- yohimbine
yohimbine and phenylephrine both decrease sedation. Use Caution/Monitor.
phenylephrine and yohimbine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor. - ziconotide
ziconotide increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and ziconotide both increase sedation. Use Caution/Monitor. - ziprasidone
ziprasidone increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
doxylamine and ziprasidone both increase sedation. Use Caution/Monitor. - zotepine
doxylamine and zotepine both increase sedation. Use Caution/Monitor.
Minor (16)
- alfuzosin
alfuzosin, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.
- asenapine
asenapine, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.
- ashwagandha
ashwagandha increases effects of doxylamine by pharmacodynamic synergism. Minor/Significance Unknown. May enhance CNS depression.
- brimonidine
brimonidine increases effects of doxylamine by pharmacodynamic synergism. Minor/Significance Unknown. Increased CNS depression.
- desmopressin
desmopressin increases effects of phenylephrine by pharmacodynamic synergism. Minor/Significance Unknown.
- doxazosin
doxazosin, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.
- eucalyptus
eucalyptus increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Minor/Significance Unknown.
doxylamine and eucalyptus both increase sedation. Minor/Significance Unknown. - moxisylyte
moxisylyte, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.
- nettle
nettle increases effects of doxylamine by pharmacodynamic synergism. Minor/Significance Unknown. (High dose nettle; theoretical interaction) May enhance CNS depression.
- phenoxybenzamine
phenoxybenzamine, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.
- phentolamine
phentolamine, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.
- prazosin
prazosin, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.
- sage
sage increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Minor/Significance Unknown.
doxylamine and sage both increase sedation. Minor/Significance Unknown. - Siberian ginseng
Siberian ginseng increases effects of doxylamine by pharmacodynamic synergism. Minor/Significance Unknown. May enhance CNS depression.
- silodosin
silodosin, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.
- terazosin
terazosin, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.
Adverse Effects
Frequency Not Defined
Hypertension
Reflex tachycardia
Severe peripheral & visceral vasoconstriction
Dizziness
Drowsiness
Excitability
Headache
Restlessness
Tremor
Dermatologic rash
Anemia blood dyscrasias (neutropenia, pancytopenia, leukopenia)
Bilirubin & alkaline phosphatase may increase
Dry mouth, throat, and nose
Thickening of mucus in nose or throat
Warnings
Contraindicated in documented hypersensitivity; asthma attacks, narrow-angle glaucoma, symptomatic prostate hypertrophy, bladder-neck obstruction, and stenosing peptic ulcer; known G-6-PD deficiency
Acetaminophen hepatotoxicity possible in chronic alcoholics following various dose levels; severe or recurrent pain or high or continued fever may indicate a serious illness; contained in many OTC products and combined use with these products may result in toxicity due to cumulative doses exceeding recommended maximum dose
Doxylamine may exacerbate angle closure glaucoma, hyperthyroidism, peptic ulcer, or urinary tract obstruction; xerostomia may occur
Phenylephrine is a vasoconstrictor and a decongestant that relieves symptoms resulting from irritation of upper respiratory tract tissue. It shrinks swollen mucous membranes, reduces nasal congestion and tissue hyperemia.
Contraindications
Documented hypersensitivity
Asthma
Narrow-angle glaucoma
Symptomatic prostate hypertrophy
Bladder-neck obstruction
Stenosing peptic ulcer
Known G-6-PD deficiency
Cautions
Acetaminophen hepatotoxicity possible in chronic alcoholics following various dose levels; severe or recurrent pain or high or continued fever may indicate a serious illness; contained in many OTC products and combined use with these products may result in toxicity due to cumulative doses exceeding recommended maximum dose
Acetaminophen: Risk for rare, but serious skin reactions that can be fatal; these reactions include Stevens-Johnson Syndrome (SJS), toxic epidermal necrolysis (TEN), and acute generalized exanthematous pustulosis (AGEP); symptoms may include skin redness, blisters and rash
Doxylamine may exacerbate angle closure glaucoma, hyperthyroidism, peptic ulcer, or urinary tract obstruction; xerostomia may occur
Phenylephrine is a vasoconstrictor and may increase blood pressure
Pregnancy & Lactation
Pregnant or breastfeeding patients should seek advice of health professional before using OTC drugs
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Acetaminophen: Blocks pain impulse generation peripherally & may inhibit the generation of prostaglandin in the CNS; reduces fever by inhibiting hypothalamic heat-regulating center
Doxylamine: Competitively blocks histamine from binding to H1 receptors; significant antimuscarinic activity & penetrates CNS, which causes pronounced tendency to induce sedation
Phenylephrine: Vasoconstrictor & decongestant that relieves symptoms resulting from irritation of upper respiratory tract tissue; shrinks swollen mucous membranes, reduces nasal congestion & tissue hyperemia
