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      Drugs & Diseases

      chlorpheniramine/dextromethorphan (OTC)

      Brand and Other Names:Children's Robitussin Cough & Cold Long-Acting, St. Joseph Cough & Cold
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      Dosing & Uses

      AdultPediatric

      Dosing Forms & Strengths

      chlorpheniramine/dextromethorphan

      softchew tablet

      • 1mg/5mg

      oral syrup

      • (1mg/7.5mg)/5mL
      • (2mg/15mg)/5mL

      tablet

      • 4mg/30mg

      Cough & Cold

      4mg chlorpheniramine/30mg dextromethorphan PO q6hr PRN

      Dosage Forms & Strengths

      chlorpheniramine/dextromethorphan

      softchew tablet

      • 1mg/5mg

      oral syrup

      • (1mg/7.5mg)/5mL
      • (2mg/15mg)/5mL

      tablet

      • 4mg/30mg

      Cough & Cold

      <6 years

      • Safety and efficacy not established

      6-12 years

      • Syrup: 2 mg chlorpheniramine/15 mg dextromethorphan PO q6hr
      • Softchew tablet: 2 mg chlorpheniramine/10 mg dextromethorphan PO q4-6hr

      >12 years

      • 4mg chlorpheniramine/30mg dextromethorphan PO q6hr PRN
      Next:

      Interactions

      Interaction Checker

      and chlorpheniramine/dextromethorphan

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                Contraindicated (0)

                  Serious - Use Alternative (17)

                  • 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.

                  • 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.

                  • benzhydrocodone/acetaminophen

                    benzhydrocodone/acetaminophen and chlorpheniramine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate

                  • buprenorphine subdermal implant

                    buprenorphine subdermal implant and chlorpheniramine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate

                  • buprenorphine transdermal

                    buprenorphine transdermal and chlorpheniramine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate

                  • 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.

                  • 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.

                  • 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

                  • 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. .

                  • lonafarnib

                    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.

                  • 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.

                  • olopatadine intranasal

                    chlorpheniramine and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

                  • sodium oxybate

                    chlorpheniramine, sodium oxybate. Either increases effects of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Profound sedation, respiratory depression, coma, and death may result if coadministered. Reserve concomitant prescribing of these drugs in patients for whom other treatment options are inadequate. Limit dosages and durations to the minimum required. Monitor closely for signs of respiratory depression and sedation.

                  • tranylcypromine

                    tranylcypromine increases effects of chlorpheniramine by Other (see comment). Avoid or Use Alternate Drug. Comment: Tranylcypromine should not be administered in combination with antihistamines because of potential additive CNS depressant effects. MAO inhibitors also prolong and intensify anticholinergic effects of antihistamines. .

                  • tucatinib

                    tucatinib will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of tucatinib with CYP3A substrates, where minimal concentration changes may lead to serious or life-threatening toxicities. If unavoidable, reduce CYP3A substrate dose according to product labeling.

                  • voxelotor

                    voxelotor will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Voxelotor increases systemic exposure of sensitive CYP3A4 substrates. Avoid coadministration with sensitive CYP3A4 substrates with a narrow therapeutic index. Consider dose reduction of the sensitive CYP3A4 substrate(s) if unable to avoid.

                  Monitor Closely (222)

                  • acrivastine

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

                  • albuterol

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

                  • alfentanil

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

                  • alprazolam

                    chlorpheniramine and alprazolam both increase sedation. 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.

                  • amisulpride

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

                  • amitriptyline

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

                  • amobarbital

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

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

                  • amoxapine

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

                  • apomorphine

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

                  • arformoterol

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

                  • aripiprazole

                    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.

                  • asenapine

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

                  • asenapine transdermal

                    asenapine transdermal and chlorpheniramine both increase sedation. Use Caution/Monitor.

                  • avapritinib

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

                  • azelastine

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

                  • baclofen

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

                  • belladonna and opium

                    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

                    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.

                  • brexanolone

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

                  • brexpiprazole

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

                  • brimonidine

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

                  • brivaracetam

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

                  • brompheniramine

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

                  • buprenorphine

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

                  • buprenorphine buccal

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

                  • butabarbital

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

                  • butalbital

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

                  • butorphanol

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

                  • caffeine

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

                  • carbinoxamine

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

                  • carisoprodol

                    chlorpheniramine and carisoprodol both increase sedation. 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.

                  • chlorpromazine

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

                  • chlorzoxazone

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

                  • cinnarizine

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

                  • clemastine

                    chlorpheniramine and clemastine both increase sedation. 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

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

                  • clonazepam

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

                  • clorazepate

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

                  • clozapine

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

                  • codeine

                    chlorpheniramine and codeine both increase sedation. 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

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

                  • cyclobenzaprine

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

                  • cyproheptadine

                    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.

                  • dantrolene

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

                  • daridorexant

                    chlorpheniramine and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

                  • 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

                    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.

                  • dexmedetomidine

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

                  • dexmethylphenidate

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

                  • dextroamphetamine

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

                  • dextromoramide

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

                  • diamorphine

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

                  • diazepam

                    chlorpheniramine and diazepam both increase sedation. 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.

                  • difelikefalin

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

                  • difenoxin hcl

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

                  • dimenhydrinate

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

                  • diphenhydramine

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

                  • diphenoxylate hcl

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

                  • dipipanone

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

                  • dobutamine

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

                  • donepezil transdermal

                    donepezil transdermal, chlorpheniramine. Either decreases effects of the other by pharmacodynamic antagonism. Use Caution/Monitor.

                  • dopamine

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

                  • dopexamine

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

                  • dosulepin

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

                  • doxepin

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

                  • doxylamine

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

                  • droperidol

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

                  • 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.

                  • 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

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

                  • epinephrine

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

                  • epinephrine racemic

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

                  • esketamine intranasal

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

                  • estazolam

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

                  • ethanol

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

                  • etomidate

                    etomidate and chlorpheniramine both increase sedation. 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.

                  • flibanserin

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

                  • fluphenazine

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

                  • flurazepam

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

                  • formoterol

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

                  • fosphenytoin

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

                  • ganaxolone

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

                  • 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.

                  • hydromorphone

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

                  • hydroxyzine

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

                  • iloperidone

                    chlorpheniramine and iloperidone both increase sedation. 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.

                  • isoproterenol

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

                  • 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.

                  • 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

                    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.

                  • lenacapavir

                    lenacapavir will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lencapavir (a moderate CYP3A4 inhibitor) may increase CYP3A4 substrates initiated within 9 months after last SC dose of lenacapavir, which may increase potential risk of adverse reactions of CYP3A4 substrates.

                  • 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.

                  • levorphanol

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

                  • lisdexamfetamine

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

                  • lofepramine

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

                  • lofexidine

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

                  • loprazolam

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

                  • lorazepam

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

                  • lormetazepam

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

                  • loxapine

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

                  • loxapine inhaled

                    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

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

                  • marijuana

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

                  • melatonin

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

                  • meperidine

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

                  • meprobamate

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

                  • metaproterenol

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

                  • metaxalone

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

                  • methadone

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

                  • methamphetamine

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

                  • methocarbamol

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

                  • methylenedioxymethamphetamine

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

                  • midazolam

                    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.

                  • 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.

                  • 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

                    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.

                  • motherwort

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

                  • moxonidine

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

                  • nabilone

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

                  • nalbuphine

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

                  • norepinephrine

                    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.

                  • olanzapine

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

                  • opium tincture

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

                  • orphenadrine

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

                  • oxazepam

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

                  • oxycodone

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

                  • oxymorphone

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

                  • paliperidone

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

                  • papaveretum

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

                  • papaverine

                    chlorpheniramine and papaverine both increase sedation. 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

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

                  • perphenazine

                    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.

                  • 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

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

                  • phentermine

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

                  • phenylephrine

                    chlorpheniramine 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

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

                  • pirbuterol

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

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

                  • prochlorperazine

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

                  • promethazine

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

                  • propofol

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

                  • propylhexedrine

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

                  • protriptyline

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

                  • quazepam

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

                  • quetiapine

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

                  • ramelteon

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

                  • risperidone

                    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.

                  • salmeterol

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

                  • scullcap

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

                  • secobarbital

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

                  • sevoflurane

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

                  • shepherd's purse

                    chlorpheniramine and shepherd's purse both increase sedation. 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

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

                  • tapentadol

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

                  • tazemetostat

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

                  • 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

                    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.

                  • thiothixene

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

                  • topiramate

                    chlorpheniramine and topiramate both increase sedation. Modify Therapy/Monitor Closely.

                  • tramadol

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

                  • trazodone

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

                  • triazolam

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

                  • triclofos

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

                  • trifluoperazine

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

                  • trimipramine

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

                  • triprolidine

                    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.

                  • xylometazoline

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

                  • yohimbine

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

                  • ziconotide

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

                  • ziprasidone

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

                  • zotepine

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

                  Minor (12)

                  • acetazolamide

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

                  • anastrozole

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

                  • ashwagandha

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

                  • brimonidine

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

                  • cyclophosphamide

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

                  • eucalyptus

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

                  • larotrectinib

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

                  • levoketoconazole

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

                  • nettle

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

                  • ribociclib

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

                  • sage

                    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.

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                  Adverse Effects

                  Frequency Not Defined

                  Sedation ranging from mild drowsiness to deep sleep

                  CNS depression

                  Excitability may occur in children

                  Dizziness

                  Impaired coordination

                  Muscular weakness

                  Anorexia

                  Nausea

                  Vomiting

                  Urinary retention

                  Blurred vision

                  Xerostomia

                  Restlessness, insomnia, tremors, euphoria, nervousness, delirium, palpitations, seizures reported infrequently

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                  Warnings

                  Contraindications

                  Hypersensitivity

                  Within 2 wk of taking a monoamine oxidase (MAO) inhibitor

                  Sedation of children

                  Cautions

                  Caution in children younger than 6 years

                  Benign prostatic hypertrophy

                  Glaucoma

                  Caution in productive cough (do not suppress expectoration of phlegm)

                  Chronic respiratory conditions (eg, asthma, COPD)

                  Alcohol consumption or other CNS depressants may increase risk for drowsiness

                  May impair ability to safely drive vehicle or operate machinery

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                  Pregnancy & Lactation

                  Pregnancy Category: C

                  Lactation: Unknown whether distributed in breast milk, caution advised

                  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: Histamine H1-receptor antagonist; sedative effect is low; antihistamine and anticholinergic activity is moderate

                  Dextromethorphan: Antitussive; derivative of levorphanol; acts on cough center in medulla

                  Absorption

                  Peak Plasma Time: 2-6 hr (chlorpheniramine); 2-3 hr (dextromethorphan)

                  Onset: 15-30 min (dextromethorphan)

                  Duration: 3-6 hr (dextromethorphan)

                  Distribution

                  Protein Bound: 69-72% (chlorpheniramine)

                  Vd: 2.5-3.2 L/kg (chlorpheniramine)

                  Metabolism

                  Metabolism: GI mucosa, liver (chlorpheniramine); hepatic P450 enzyme CYP2D6 (dextromethorphan)

                  Metabolites: Monodesmethylchlorpheniramine, didesmethylchlorpheniramine

                  Elimination

                  Half-Life: 12-43 hr (chlorpheniramine); 2-4 hr (extensive dextromethorphan metabolizers); 24 hr (poor dextromethorphan metabolizers)

                  Excretion: Predominantly urine (chlorpheniramine and dextromethorphan)

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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.
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