acetaminophen/chlorpheniramine/phenylephrine (OTC)

Brand and Other Names:Tylenol Allergy Multi-Symptom, Dristan Cold, more...Children's Tylenol Plus Cold, Tylenol Sinus Congestion & Pain Nighttime, Robitussin Peak Cold Nighttime Nasal Relief
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Dosing & Uses

AdultPediatric

Dosage Forms & Strengths

acetaminophen/chlorpheniramine/phenylephrine

tablet

  • 325mg/2mg/5mg

Relief of Cold & Flu Symptoms

Dristan Cold: 2 tablets PO q4hr; not to exceed 12 tablets/day

Tylenol Allergy Multi-Symptom: 2 tablets PO q4hr; not to exceed 12 tablets/day

Tylenol Sinus Congestion & Pain Nighttime: 2 tablets PO q4hr; not to exceed 12 tablets/day

Robitussin Peak Cold Nighttime Nasal Relief: 2 tablets q4hr prn; not to exceed 12 tablets/day

Dosage Forms & Strengths

acetaminophen/chlorpheniramine/phenylephrine

tablet

  • 325mg/2mg/5mg

Relief of Cold & Flu Symptoms

<12 years

  • : Ask a peditrician

>12 years

  • Dristan Cold: 2 tablets PO q4hr; not to exceed 12 tablets/day
  • Tylenol Allergy Multi-Symptom: 2 tablets PO q4hr; not to exceed 12 tablets/day
  • Tylenol Sinus Congestion & Pain Nighttime: 2 tablets PO q4hr; not to exceed 12 tablets/day
  • Robitussin Peak Cold Nighttime Nasal Relief: 2 tablets q4hr prn
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Interactions

Interaction Checker

and acetaminophen/chlorpheniramine/phenylephrine

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            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 (33)

            • abametapir

              abametapir will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP3A4 substrates. If not feasible, avoid use of abametapir.

            • 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.

            • apalutamide

              apalutamide will decrease the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.

            • cabergoline

              cabergoline, phenylephrine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.

            • calcium/magnesium/potassium/sodium oxybates

              chlorpheniramine, 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.

            • eluxadoline

              chlorpheniramine, eluxadoline. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Avoid coadministration with other drugs that cause constipation. Increases risk for constipation related serious adverse reactions.

            • 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.

            • fexinidazole

              fexinidazole will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates.

            • idelalisib

              idelalisib will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substrates

            • 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 chlorpheniramine 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.

            • 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.

            • lonafarnib

              acetaminophen will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of lonafarnib (a sensitive CYP3A substrate) with weak CYP3A inhibitors is unavoidable, reduce to, or continue lonafarnib at starting dose. Closely monitor for arrhythmias and events (eg, syncope, heart palpitations) since lonafarnib effect on QT interval is unknown.

              lonafarnib will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with sensitive CYP3A substrates. If coadministration unavoidable, monitor for adverse reactions and reduce CYP3A substrate dose in accordance with product labeling.

            • 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.

            • pexidartinib

              acetaminophen and pexidartinib both increase Other (see comment). Avoid or Use Alternate Drug. Pexidartinib can cause hepatotoxicity. Avoid coadministration of pexidartinib with other products know to cause hepatoxicity.

            • methoxyflurane

              methoxyflurane increases toxicity of phenylephrine by Mechanism: unknown. Avoid or Use Alternate Drug. Risk of V tach, HTN.

            • methylergonovine

              methylergonovine, phenylephrine. Mechanism: pharmacodynamic synergism. Contraindicated. Additive vasospasm; risk of hypertension.

            • metoclopramide intranasal

              chlorpheniramine, 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.

            • pretomanid

              acetaminophen, pretomanid. Either increases toxicity of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Pretomanid regimen associated with hepatotoxicity. Avoid alcohol and hepatotoxic agents, including herbal supplements and drugs other than bedaquiline and linezolid.

            • propofol

              propofol increases levels of phenylephrine by decreasing metabolism. Contraindicated.

            Monitor Closely (284)

            • albuterol

              albuterol and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

              chlorpheniramine increases and albuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              albuterol and phenylephrine both decrease sedation. Use Caution/Monitor.

            • alfentanil

              alfentanil increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and alfentanil both increase sedation. Use Caution/Monitor.

            • alprazolam

              chlorpheniramine and alprazolam both increase sedation. Use Caution/Monitor.

              alprazolam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • amifampridine

              chlorpheniramine 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.

            • amitriptyline

              chlorpheniramine 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 will decrease the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              chlorpheniramine and amobarbital both increase sedation. Use Caution/Monitor.

            • amoxapine

              amoxapine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and amoxapine both increase sedation. Use Caution/Monitor.

            • apalutamide

              apalutamide will decrease the level or effect of acetaminophen by increasing elimination. Use Caution/Monitor. Apalutamide induces UGT and may decrease systemic exposure of drugs that are UGT substrates.

            • apomorphine

              chlorpheniramine 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.

            • arformoterol

              chlorpheniramine increases and arformoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • aripiprazole

              aripiprazole increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and aripiprazole both increase sedation. Use Caution/Monitor.

            • armodafinil

              chlorpheniramine increases and armodafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              armodafinil and phenylephrine both decrease sedation. Use Caution/Monitor.

            • atogepant

              acetaminophen will increase the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. 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

              acetaminophen will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • axitinib

              acetaminophen increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • azelastine

              azelastine and chlorpheniramine both increase sedation. Use Caution/Monitor.

            • azelastine

              azelastine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • baclofen

              chlorpheniramine 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.

              chlorpheniramine and belladonna and opium both increase sedation. Use Caution/Monitor.

            • belzutifan

              belzutifan will decrease the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. If unable to avoid coadministration of belzutifan with sensitive CYP3A4 substrates, consider increasing the sensitive CYP3A4 substrate dose in accordance with its prescribing information.

            • benperidol

              benperidol increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • benperidol

              chlorpheniramine and benperidol both increase sedation. Use Caution/Monitor.

            • benzphetamine

              chlorpheniramine increases and benzphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              benzphetamine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

              benzphetamine and phenylephrine both decrease sedation. Use Caution/Monitor.

            • brexanolone

              brexanolone, chlorpheniramine. Either increases toxicity of the other by 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 chlorpheniramine both increase sedation. Use Caution/Monitor.

            • bupivacaine implant

              acetaminophen, bupivacaine implant. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Local anesthetics may increase the risk of developing methemoglobinemia when concurrently exposed to drugs that also cause methemoglobinemia.

            • buprenorphine

              chlorpheniramine 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

              chlorpheniramine and buprenorphine buccal both increase sedation. Use Caution/Monitor.

            • busulfan

              acetaminophen increases levels of busulfan by decreasing metabolism. Use Caution/Monitor. Use of acetaminophen prior to (< 72 hours) or concurrently with busulfan may result in decreased clearance of busulfan due to acetaminophen-induced decreases in glutathione levels.

            • butabarbital

              butabarbital increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and butabarbital both increase sedation. Use Caution/Monitor.

            • butalbital

              chlorpheniramine and butalbital both increase sedation. Use Caution/Monitor.

              butalbital increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • butorphanol

              chlorpheniramine and butorphanol both increase sedation. Use Caution/Monitor.

              butorphanol increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • caffeine

              chlorpheniramine increases and caffeine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              caffeine and phenylephrine both decrease sedation. Use Caution/Monitor.

            • carbinoxamine

              carbinoxamine and chlorpheniramine both increase sedation. Use Caution/Monitor.

              carbinoxamine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • carisoprodol

              chlorpheniramine and carisoprodol both increase sedation. Use Caution/Monitor.

            • chloral hydrate

              chloral hydrate increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • cenobamate

              cenobamate will decrease the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.

              cenobamate, chlorpheniramine. Either increases effects of the other by sedation. Use Caution/Monitor.

            • chloral hydrate

              chlorpheniramine and chloral hydrate both increase sedation. Use Caution/Monitor.

            • chlordiazepoxide

              chlorpheniramine and chlordiazepoxide 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.

            • chlorpromazine

              chlorpheniramine and chlorpromazine both increase sedation. Use Caution/Monitor.

            • chlorpromazine

              chlorpromazine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. 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.

            • chlorzoxazone

              chlorpheniramine and chlorzoxazone both increase sedation. Use Caution/Monitor.

            • cinnarizine

              chlorpheniramine and cinnarizine both increase sedation. Use Caution/Monitor.

              cinnarizine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • clemastine

              chlorpheniramine and clemastine both increase sedation. Use Caution/Monitor.

              clemastine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • clobazam

              chlorpheniramine, 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

              chlorpheniramine and clomipramine both increase sedation. Use Caution/Monitor.

            • clonazepam

              clonazepam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and clonazepam both increase sedation. Use Caution/Monitor.

            • clorazepate

              chlorpheniramine and clorazepate both increase sedation. Use Caution/Monitor.

              clorazepate increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • clozapine

              clozapine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and clozapine both increase sedation. Use Caution/Monitor.

            • codeine

              chlorpheniramine 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.

            • crofelemer

              crofelemer increases levels of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Crofelemer has the potential to inhibit CYP3A4 at concentrations expected in the gut; unlikely to inhibit systemically because minimally absorbed.

            • cyclizine

              cyclizine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • cyclizine

              chlorpheniramine and cyclizine both increase sedation. Use Caution/Monitor.

            • cyclobenzaprine

              chlorpheniramine 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.

              chlorpheniramine and cyproheptadine both increase sedation. Use Caution/Monitor.

            • dabrafenib

              dabrafenib will decrease the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

            • dapsone topical

              acetaminophen increases toxicity of dapsone topical by altering metabolism. Modify Therapy/Monitor Closely. May induce methemoglobinemia .

            • desipramine

              desipramine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • dantrolene

              chlorpheniramine and dantrolene both increase sedation. Use Caution/Monitor.

            • desflurane

              desflurane and chlorpheniramine both increase sedation. Use Caution/Monitor.

            • desipramine

              chlorpheniramine and desipramine both increase sedation. Use Caution/Monitor.

            • deutetrabenazine

              chlorpheniramine 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.

              chlorpheniramine and dexchlorpheniramine both increase sedation. Use Caution/Monitor.

            • dexfenfluramine

              chlorpheniramine increases and dexfenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              dexfenfluramine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

              dexfenfluramine and phenylephrine both decrease sedation. Use Caution/Monitor.

            • dexmedetomidine

              dexmedetomidine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and dexmedetomidine both increase sedation. Use Caution/Monitor.

            • dexmethylphenidate

              dexmethylphenidate and phenylephrine both decrease sedation. Use Caution/Monitor.

              chlorpheniramine increases and dexmethylphenidate decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              dexmethylphenidate and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • dextroamphetamine

              dextroamphetamine and phenylephrine both decrease sedation. Use Caution/Monitor.

              chlorpheniramine increases and dextroamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              dextroamphetamine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • dextromoramide

              chlorpheniramine and dextromoramide both increase sedation. Use Caution/Monitor.

              dextromoramide increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • diamorphine

              chlorpheniramine 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

              chlorpheniramine and diazepam 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, chlorpheniramine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration may potentiate the CNS-depressant effects of each drug.

            • diethylpropion

              chlorpheniramine increases and diethylpropion decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • difenoxin hcl

              difenoxin hcl increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and difenoxin hcl both increase sedation. Use Caution/Monitor.

            • dimenhydrinate

              dimenhydrinate increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and dimenhydrinate both increase sedation. Use Caution/Monitor.

            • diphenhydramine

              diphenhydramine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and diphenhydramine both increase sedation. Use Caution/Monitor.

            • diphenoxylate hcl

              chlorpheniramine and diphenoxylate hcl both increase sedation. Use Caution/Monitor.

              diphenoxylate hcl increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • dipipanone

              chlorpheniramine 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

              chlorpheniramine increases and dobutamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              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.

            • dopamine

              chlorpheniramine increases and dopamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              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

              chlorpheniramine increases and dopexamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              dopexamine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

              dopexamine and phenylephrine both decrease sedation. Use Caution/Monitor.

            • dosulepin

              chlorpheniramine 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.

            • doxepin

              chlorpheniramine and doxepin both increase sedation. Use Caution/Monitor.

            • doxylamine

              chlorpheniramine and doxylamine both increase sedation. Use Caution/Monitor.

            • droperidol

              droperidol increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine 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

            • efavirenz

              efavirenz will decrease the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • elagolix

              elagolix will decrease the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.

            • eltrombopag

              eltrombopag increases levels of acetaminophen by decreasing metabolism. Use Caution/Monitor. UGT inhibition; significance of interaction unclear.

            • elvitegravir/cobicistat/emtricitabine/tenofovir DF

              elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. CYP3A4 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.

            • ephedrine

              ephedrine, phenylephrine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor.

              ephedrine and phenylephrine both decrease sedation. Use Caution/Monitor.

              chlorpheniramine increases and ephedrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              ephedrine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. 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.

              chlorpheniramine increases and epinephrine decreases sedation. Effect of interaction is not clear, use caution. 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

              chlorpheniramine increases and epinephrine racemic decreases sedation. Effect of interaction is not clear, use caution. 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.

            • esketamine intranasal

              esketamine intranasal, chlorpheniramine. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.

            • estazolam

              estazolam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and estazolam both increase sedation. Use Caution/Monitor.

            • ethanol

              ethanol increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and ethanol both increase sedation. Use Caution/Monitor.

            • etomidate

              etomidate and chlorpheniramine both increase sedation. Use Caution/Monitor.

            • exenatide injectable solution

              exenatide injectable solution will decrease the level or effect of acetaminophen by unspecified interaction mechanism. Use Caution/Monitor. To avoid potential interaction, give acetaminophen at least 1 hour before or 4 hours after exenatide injection.

            • exenatide injectable suspension

              exenatide injectable suspension will decrease the level or effect of acetaminophen by unspecified interaction mechanism. Use Caution/Monitor. To avoid potential interaction, give acetaminophen at least 1 hour before or 4 hours after exenatide injection.

            • 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.

            • fedratinib

              fedratinib will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.

            • fenfluramine

              chlorpheniramine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • fentanyl

              fentanyl, chlorpheniramine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with anticholinergics may increase risk for urinary retention and/or severe constipation, which may lead to paralytic ileus.

            • fentanyl intranasal

              fentanyl intranasal, chlorpheniramine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with anticholinergics may increase risk for urinary retention and/or severe constipation, which may lead to paralytic ileus.

            • fentanyl transdermal

              fentanyl transdermal, chlorpheniramine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with anticholinergics may increase risk for urinary retention and/or severe constipation, which may lead to paralytic ileus.

            • fentanyl transmucosal

              fentanyl transmucosal, chlorpheniramine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with anticholinergics may increase risk for urinary retention and/or severe constipation, which may lead to paralytic ileus.

            • finerenone

              acetaminophen will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or moderate CYP3A4 inhibitors. Adjust finererone dosage as needed.

            • flibanserin

              chlorpheniramine and flibanserin both increase sedation. Modify Therapy/Monitor Closely. Risk for sedation increased if flibanserin is coadministration with other CNS depressants.

              acetaminophen will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased flibanserin adverse effects may occur if coadministered with multiple weak CYP3A4 inhibitors.

            • fluphenazine

              fluphenazine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and fluphenazine both increase sedation. 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.

            • imatinib

              imatinib decreases levels of acetaminophen by decreasing hepatic clearance. Modify Therapy/Monitor Closely. In vitro, imatinib was found to inhibit acetaminophen O-glucuronidation (Ki value of 58.5 micro-M) at therapeutic levels; avoid chronic acetaminophen therapy with imatinib; if occasional acetaminophen administered, do not exceed 1300 mg/day.

            • flurazepam

              chlorpheniramine and flurazepam both increase sedation. Use Caution/Monitor.

              flurazepam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • formoterol

              chlorpheniramine increases and formoterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              formoterol and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

              formoterol and phenylephrine both decrease sedation. Use Caution/Monitor.

            • fosphenytoin

              fosphenytoin will decrease the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • haloperidol

              haloperidol increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • gabapentin

              gabapentin, chlorpheniramine. 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, chlorpheniramine. 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.

            • glycopyrronium tosylate topical

              glycopyrronium tosylate topical, chlorpheniramine. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Coadministration of glycopyrronium tosylate topical with other anticholinergic medications may result in additive anticholinergic adverse effects.

            • gotu kola

              gotu kola increases effects of chlorpheniramine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.

            • haloperidol

              chlorpheniramine and haloperidol both increase sedation. Use Caution/Monitor.

            • hawthorn

              hawthorn increases effects of chlorpheniramine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.

            • hops

              hops increases effects of chlorpheniramine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.

            • hyaluronidase

              chlorpheniramine 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.

            • hydralazine

              hydralazine, phenylephrine. Mechanism: pharmacodynamic antagonism. Use Caution/Monitor. Sympathomimetics can antagonize the activity of some antihypertensive agents.

            • hydromorphone

              chlorpheniramine 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

              chlorpheniramine and hydroxyzine both increase sedation. Use Caution/Monitor.

              hydroxyzine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • iloperidone

              chlorpheniramine and iloperidone both increase sedation. Use Caution/Monitor.

              iloperidone increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              iloperidone increases levels of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Iloperidone is a time-dependent CYP3A inhibitor and may lead to increased plasma levels of drugs predominantly eliminated by CYP3A4.

            • imipramine

              chlorpheniramine and imipramine both increase sedation. Use Caution/Monitor.

              imipramine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • 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.

            • isoniazid

              isoniazid will increase the level or effect of acetaminophen by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.

            • isoproterenol

              chlorpheniramine increases and isoproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • 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.

            • istradefylline

              istradefylline will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.

            • ivacaftor

              acetaminophen increases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor when coadministered with weak CYP3A4 inhibitors .

            • kava

              kava increases effects of chlorpheniramine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.

            • ketamine

              ketamine and chlorpheniramine both increase sedation. Use Caution/Monitor.

            • ketotifen, ophthalmic

              chlorpheniramine 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, chlorpheniramine. 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.

            • lemborexant

              acetaminophen will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Lower nightly dose of lemborexant recommended if coadministered with weak CYP3A4 inhibitors. See drug monograph for specific dosage modification.

            • 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.

            • lemborexant

              lemborexant, chlorpheniramine. Either increases effects of the other by sedation. Modify Therapy/Monitor Closely. Dosage adjustment may be necessary if lemborexant is coadministered with other CNS depressants because of potentially additive effects.

            • letermovir

              letermovir increases levels of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • levalbuterol

              chlorpheniramine increases and levalbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • levonorgestrel oral/ethinylestradiol/ferrous bisglycinate

              levonorgestrel oral/ethinylestradiol/ferrous bisglycinate will decrease the level or effect of acetaminophen by unknown mechanism. Use Caution/Monitor.

              acetaminophen increases levels of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by decreasing hepatic clearance. Use Caution/Monitor. Coadministration of ascorbic acid and certain combined hormonal contraceptives (CHCs) containing EE may increase plasma EE concentrations, possibly by inhibition of conjugation.

            • levorphanol

              levorphanol increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and levorphanol both increase sedation. Use Caution/Monitor.

            • lisdexamfetamine

              lisdexamfetamine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

              chlorpheniramine increases and lisdexamfetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              lisdexamfetamine and phenylephrine both decrease sedation. Use Caution/Monitor.

            • lixisenatide

              lixisenatide will decrease the level or effect of acetaminophen by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. GLP1 agonists delay gastric emptying, which may affect absorption of concomitantly administered oral medications. No effects on acetaminophen Cmax and Tmax were observed when acetaminophen was administered 1 hr before lixisenatide. When administered 1 or 4 hr after lixisenatide, acetaminophen Cmax was decreased by 29% and 31% respectively and median Tmax was delayed by 2 and 1.75 hr, respectively.

            • lofepramine

              chlorpheniramine and lofepramine both increase sedation. Use Caution/Monitor.

              lofepramine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • lofexidine

              chlorpheniramine and lofexidine both increase sedation. Use Caution/Monitor.

              lofexidine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • lomitapide

              acetaminophen increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lomitapide dose should not exceed 30 mg/day.

            • loprazolam

              loprazolam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and loprazolam both increase sedation. Use Caution/Monitor.

            • lorazepam

              chlorpheniramine and lorazepam both increase sedation. Use Caution/Monitor.

              lorazepam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • lormetazepam

              chlorpheniramine and lormetazepam both increase sedation. Use Caution/Monitor.

              lormetazepam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • loxapine

              chlorpheniramine 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.

              chlorpheniramine and loxapine inhaled both increase sedation. Use Caution/Monitor.

            • lurasidone

              lurasidone, chlorpheniramine. 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

              chlorpheniramine and maprotiline both increase sedation. Use Caution/Monitor.

            • marijuana

              chlorpheniramine 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

              melatonin increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and melatonin both increase sedation. Use Caution/Monitor.

            • meperidine

              chlorpheniramine and meperidine both increase sedation. Use Caution/Monitor.

              meperidine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • meprobamate

              meprobamate increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and meprobamate both increase sedation. Use Caution/Monitor.

            • metaproterenol

              metaproterenol and phenylephrine both decrease sedation. Use Caution/Monitor.

              chlorpheniramine increases and metaproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              metaproterenol and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • metaxalone

              chlorpheniramine and metaxalone both increase sedation. Use Caution/Monitor.

            • methadone

              methadone increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • methadone

              chlorpheniramine and methadone both increase sedation. Use Caution/Monitor.

            • methamphetamine

              methamphetamine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

              chlorpheniramine increases and methamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              methamphetamine and phenylephrine both decrease sedation. Use Caution/Monitor.

            • methocarbamol

              chlorpheniramine and methocarbamol both increase sedation. Use Caution/Monitor.

            • methyldopa

              methyldopa increases effects of phenylephrine by unknown mechanism. Use Caution/Monitor.

            • methylenedioxymethamphetamine

              chlorpheniramine increases and methylenedioxymethamphetamine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              methylenedioxymethamphetamine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

              methylenedioxymethamphetamine and phenylephrine both decrease sedation. Use Caution/Monitor.

            • midazolam

              midazolam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and midazolam both increase sedation. Use Caution/Monitor.

            • midazolam intranasal

              midazolam intranasal, chlorpheniramine. Either increases effects of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase the risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.

              acetaminophen will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of mild CYP3A4 inhibitors with midazolam intranasal may cause higher midazolam systemic exposure, which may prolong sedation.

            • 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.

            • mipomersen

              mipomersen, acetaminophen. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Both drugs have potential to increase hepatic enzymes; monitor LFTs.

            • midodrine

              chlorpheniramine increases and midodrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • mirtazapine

              chlorpheniramine 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.

            • mitotane

              mitotane decreases levels of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.

            • modafinil

              modafinil and phenylephrine both decrease sedation. Use Caution/Monitor.

            • modafinil

              chlorpheniramine increases and modafinil decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • morphine

              chlorpheniramine and morphine both increase sedation. Use Caution/Monitor.

              morphine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • motherwort

              chlorpheniramine 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.

              chlorpheniramine and moxonidine both increase sedation. Use Caution/Monitor.

            • nabilone

              chlorpheniramine and nabilone both increase sedation. Use Caution/Monitor.

              nabilone increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • nadolol

              nadolol increases effects of phenylephrine by pharmacodynamic synergism. Use Caution/Monitor. Risk of acute hypertensive episode (rare).

            • nalbuphine

              chlorpheniramine 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.

              chlorpheniramine increases and norepinephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • nortriptyline

              chlorpheniramine and nortriptyline both increase sedation. Use Caution/Monitor.

              nortriptyline increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • olanzapine

              chlorpheniramine and olanzapine both increase sedation. Use Caution/Monitor.

              olanzapine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • 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

            • opium tincture

              chlorpheniramine and opium tincture both increase sedation. Use Caution/Monitor.

            • opium tincture

              opium tincture increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • orphenadrine

              chlorpheniramine 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.

              chlorpheniramine and oxazepam both increase sedation. Use Caution/Monitor.

            • oxycodone

              oxycodone increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and oxycodone both increase sedation. 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

              chlorpheniramine 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

              chlorpheniramine 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

              chlorpheniramine and papaveretum both increase sedation. Use Caution/Monitor.

              papaveretum increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • papaverine

              chlorpheniramine 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 chlorpheniramine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.

            • pentazocine

              chlorpheniramine and pentazocine both increase sedation. Use Caution/Monitor.

            • pentobarbital

              pentobarbital increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and pentobarbital both increase sedation. 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.

              chlorpheniramine and perphenazine both increase sedation. Use Caution/Monitor.

            • phendimetrazine

              chlorpheniramine increases and phendimetrazine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              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 chlorpheniramine 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 increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • phenobarbital

              chlorpheniramine and phenobarbital both increase sedation. Use Caution/Monitor.

            • phentermine

              phentermine and phenylephrine both decrease sedation. Use Caution/Monitor.

              chlorpheniramine increases and phentermine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              phentermine and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

            • phenylephrine

              chlorpheniramine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • pholcodine

              pholcodine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • phenylephrine PO

              chlorpheniramine increases and phenylephrine PO decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor. .

            • pholcodine

              chlorpheniramine and pholcodine both increase sedation. Use Caution/Monitor.

            • pimozide

              pimozide increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine 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).

            • pirbuterol

              chlorpheniramine increases and pirbuterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • 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, chlorpheniramine. 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 increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and primidone both increase sedation. Use Caution/Monitor.

            • prochlorperazine

              chlorpheniramine 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

              chlorpheniramine and promethazine 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 chlorpheniramine 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

              chlorpheniramine 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

              chlorpheniramine 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

              chlorpheniramine and quazepam 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.

              chlorpheniramine and quetiapine both increase sedation. Use Caution/Monitor.

            • ramelteon

              chlorpheniramine 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.

            • risperidone

              risperidone increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and risperidone both increase sedation. Use Caution/Monitor.

            • rucaparib

              rucaparib will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP3A4 substrates, if clinically indicated.

            • 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.

            • salmeterol

              chlorpheniramine increases and salmeterol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              salmeterol and phenylephrine both increase sympathetic (adrenergic) effects, including increased blood pressure and heart rate. Use Caution/Monitor.

              salmeterol and phenylephrine both decrease sedation. Use Caution/Monitor.

            • scullcap

              chlorpheniramine and scullcap both increase sedation. Use Caution/Monitor.

              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.

              chlorpheniramine and secobarbital 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 chlorpheniramine both increase sedation. Use Caution/Monitor.

            • shepherd's purse

              chlorpheniramine 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, chlorpheniramine. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.

            • sufentanil

              sufentanil increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and sufentanil both increase sedation. Use Caution/Monitor.

            • tapentadol

              chlorpheniramine and tapentadol both increase sedation. Use Caution/Monitor.

              tapentadol increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • tazemetostat

              acetaminophen will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

              tazemetostat will decrease the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • temazepam

              temazepam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • tetracaine

              tetracaine, acetaminophen. Other (see comment). Use Caution/Monitor. Comment: Monitor for signs of methemoglobinemia when methemoglobin-inducing drugs are coadministered.

            • tecovirimat

              tecovirimat will decrease the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.

            • temazepam

              chlorpheniramine and temazepam 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.

              chlorpheniramine increases and terbutaline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • thioridazine

              chlorpheniramine and thioridazine both increase sedation. Use Caution/Monitor.

              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

              chlorpheniramine 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).

            • tinidazole

              acetaminophen will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

            • topiramate

              chlorpheniramine 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

              chlorpheniramine 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

              chlorpheniramine 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

              chlorpheniramine and triazolam both increase sedation. Use Caution/Monitor.

              triazolam increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

            • triclofos

              chlorpheniramine 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

              chlorpheniramine 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.

              chlorpheniramine and trimipramine both increase sedation. Use Caution/Monitor.

            • triprolidine

              triprolidine increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.

              chlorpheniramine and triprolidine both increase sedation. Use Caution/Monitor.

            • valerian

              valerian increases effects of chlorpheniramine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.

            • warfarin

              acetaminophen increases effects of warfarin by unknown mechanism. Use Caution/Monitor.

            • 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.

            Minor (64)

            • acetazolamide

              acetazolamide decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • albiglutide

              albiglutide decreases levels of acetaminophen by unspecified interaction mechanism. Minor/Significance Unknown.

            • alfuzosin

              alfuzosin, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.

            • antithrombin alfa

              acetaminophen increases effects of antithrombin alfa by unknown mechanism. Minor/Significance Unknown.

            • antithrombin III

              acetaminophen increases effects of antithrombin III by unknown mechanism. Minor/Significance Unknown.

            • argatroban

              acetaminophen increases effects of argatroban by unknown mechanism. Minor/Significance Unknown.

            • asenapine

              asenapine, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.

            • ashwagandha

              ashwagandha increases effects of chlorpheniramine by pharmacodynamic synergism. Minor/Significance Unknown. May enhance CNS depression.

            • bemiparin

              acetaminophen increases effects of bemiparin by unknown mechanism. Minor/Significance Unknown.

            • bivalirudin

              acetaminophen increases effects of bivalirudin by unknown mechanism. Minor/Significance Unknown.

            • brimonidine

              brimonidine increases effects of chlorpheniramine by pharmacodynamic synergism. Minor/Significance Unknown. Increased CNS depression.

            • carbamazepine

              carbamazepine decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • cholestyramine

              cholestyramine decreases levels of acetaminophen by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

            • clonazepam

              clonazepam decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • colestipol

              colestipol decreases levels of acetaminophen by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

            • dalteparin

              acetaminophen increases effects of dalteparin by unknown mechanism. Minor/Significance Unknown.

            • desmopressin

              desmopressin increases effects of phenylephrine by pharmacodynamic synergism. Minor/Significance Unknown.

            • diazepam

              diazepam decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • disulfiram

              disulfiram will increase the level or effect of acetaminophen by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.

            • doxazosin

              doxazosin, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.

            • enoxaparin

              acetaminophen increases effects of enoxaparin by unknown mechanism. Minor/Significance Unknown.

            • ethanol

              ethanol will decrease the level or effect of acetaminophen by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.

              ethanol increases toxicity of acetaminophen by decreasing metabolism. Minor/Significance Unknown.

            • ethosuximide

              ethosuximide decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • eucalyptus

              eucalyptus increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Minor/Significance Unknown.

              chlorpheniramine and eucalyptus both increase sedation. Minor/Significance Unknown.

            • felbamate

              felbamate decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • fondaparinux

              acetaminophen increases effects of fondaparinux by unknown mechanism. Minor/Significance Unknown.

            • fosphenytoin

              fosphenytoin decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • gabapentin

              gabapentin decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • gabapentin enacarbil

              gabapentin enacarbil decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • green tea

              green tea increases effects of acetaminophen by pharmacodynamic synergism. Minor/Significance Unknown. (Theoretical, due to caffeine content).

            • heparin

              acetaminophen increases effects of heparin by unknown mechanism. Minor/Significance Unknown.

            • isoniazid

              isoniazid increases toxicity of acetaminophen by unknown mechanism. Minor/Significance Unknown.

            • lacosamide

              lacosamide decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • lamotrigine

              lamotrigine decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • levetiracetam

              levetiracetam decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • liraglutide

              liraglutide decreases levels of acetaminophen by unspecified interaction mechanism. Minor/Significance Unknown.

            • lorazepam

              lorazepam decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • methsuximide

              methsuximide decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • metoclopramide

              metoclopramide increases levels of acetaminophen by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

            • metronidazole

              metronidazole will increase the level or effect of acetaminophen by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.

            • moxisylyte

              moxisylyte, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.

            • nettle

              nettle increases effects of chlorpheniramine by pharmacodynamic synergism. Minor/Significance Unknown. (High dose nettle; theoretical interaction) May enhance CNS depression.

            • oxcarbazepine

              oxcarbazepine decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • oxybutynin

              oxybutynin decreases levels of acetaminophen by unspecified interaction mechanism. Minor/Significance Unknown.

            • oxybutynin topical

              oxybutynin topical decreases levels of acetaminophen by unspecified interaction mechanism. Minor/Significance Unknown.

            • oxybutynin transdermal

              oxybutynin transdermal decreases levels of acetaminophen by unspecified interaction mechanism. Minor/Significance Unknown.

            • phenindione

              acetaminophen increases effects of phenindione by unknown mechanism. Minor/Significance Unknown.

            • phenobarbital

              phenobarbital decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • 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.

            • phenytoin

              phenytoin decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • prazosin

              prazosin, phenylephrine. Either decreases effects of the other by Mechanism: pharmacodynamic antagonism. Minor/Significance Unknown.

            • primidone

              primidone decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • protamine

              acetaminophen increases effects of protamine by unknown mechanism. Minor/Significance Unknown.

            • ribociclib

              ribociclib will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • rifabutin

              rifabutin decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • rifampin

              rifampin decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • rufinamide

              rufinamide decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

            • ruxolitinib

              acetaminophen will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

            • sage

              sage increases and phenylephrine decreases sedation. Effect of interaction is not clear, use caution. Minor/Significance Unknown.

              chlorpheniramine and sage both increase sedation. Minor/Significance Unknown.

            • Siberian ginseng

              Siberian ginseng increases effects of chlorpheniramine 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.

            • tiagabine

              tiagabine decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

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            Adverse Effects

            Frequency Not Defined

            Hypotension

            Hypertension

            Palpitations

            Reflex tachycardia

            Severe peripheral and visceral vasoconstriction

            Tachycardia

            Confusion

            Depression

            Distress

            Dizziness

            Euphoria

            Excitability

            Fatigue

            Headache

            Insomnia

            Irritability

            Restlessness

            Sedation

            Tremors

            Dermatologic rash

            Anorexia

            Agranulocytosis

            Anemia blood dyscrasias (neutropenia, pancytopenia, leukopenia)

            Hemolytic anemia

            Thrombocytopenia

            Bilirubin and alkaline phosphatase may increase

            Thickening of bronchial secretions

            Wheezing

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            Warnings

            Contraindications

            Contraindicated in documented hypersensitivity; asthma attacks, narrow-angle glaucoma, symptomatic prostate hypertrophy, bladder-neck obstruction, and stenosing peptic ulcer; known G-6-PD deficiency

            Chlorpheniramine may cause significant confusional symptoms; not for administration to < 2 years of age

            Use of MAO inhibitor within 14 days

            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

            Cautions

            Caution in elderly patients, hyperthyroidism, myocardial disease, bradycardia, partial heart block or severe arteriosclerosis when administering phenylephrine; in hypovolemia, phenylephrine use is not a substitute for replacement of blood, fluids and electrolytes, and plasma (promptly restore with loss); dilute IV and administer via large vein; extravasation precautions required

            Caution in asthma, bladder neck obstruction, cardiovascular disease, COPD, GI obstruction, glaucoma, hepatic impairment, hyperthyroidism, increased intraocular pressure, malnutrition, renal impairment, elderly patients, patients taking CNS depressants or < 6 years of age with chlorpheniramine products

            Caution in severe hypovolemia if taking acetaminophen products

            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

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            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.

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            Pharmacology

            Mechanism of Action

            Chlorpheniramine blocks muscle responses in histamine and acts as an antagonism of the constrictor effects of histamine on respiratory smooth muscle.

            Acetaminophen blocks pain impulse generation peripherally and may inhibit the generation of prostaglandin in the CNS. Reduces fever by inhibiting the hypothalamic heat-regulating center.

            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.

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            Images

            No images available for this drug.
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            Patient Handout

            A Patient Handout is not currently available for this monograph.
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            Medscape prescription drug monographs are based on FDA-approved labeling information, unless otherwise noted, combined with additional data derived from primary medical literature.