Dosing & Uses
Dosage Forms & Strengths
tablet
- 4mg
- 8mg
- 12mg
syrup
- 2mg/5mL
Allergic Rhinitis
Tablets or syrup: 4 mg PO q4-6hr; not to exceed 24 mg/day
Extended-release tablets: 8 mg PO q8-12hr or 12 mg q12hr; not to exceed 24 mg/day
Extended-release capsules: 12 mg PO qDay; not to exceed 24 mg/day
Sustained-release capsules: 8-12 mg PO q8-12hr, up to 16-24 mg/day
Additional Information
See also combo with hydrocodone (Tussionex)
Other Indications & Uses
Perennial & seasonal allergic & vasomotor rhinitis, relief of symptoms from colds, urticaria, angioedema, anaphylactic reactions, pruritus, allergic conjunctivitis
Dosage Forms & Strengths
tablet
- 4mg
- 8mg
- 12mg
suspension
- 2mg/mL
syrup
- 2mg/5mL
Allergic Rhinitis
<2 years: Safety & efficacy not established
2-6 years: 1 mg PO q4-6hr; not to exceed 6 mg/day
6-12 years: 2 mg PO q4-6hr; not to exceed 12 mg/day or sustained release HS
>12 years
- Tablets or syrup: 4 mg PO q4-6hr; not to exceed 24 mg/day
- Extended-release tablets: 8 mg PO q8-12hr or 12 mg q12hr; not to exceed 24 mg/day
- Extended-release capsules: 12 mg PO qDay; not to exceed 24 mg/day
- Sustained-release capsules: 8-12 mg PO q8-12hr, up to 16-24 mg/day
4 mg PO qDay or q12hr
Sustained-release: 8 mg PO qHS
Nonanticholinergic antihistamines should be considered first when treating allergic reactions (Beers Criteria)
Avoid use in elderly because of high incidence of anticholinergic effects
Clearance reduced with advanced age, greater risk of confusion, dry mouth, constipation, and other anticholinergic effects and toxicity
May exacerbate existing lower urinary conditions or benign prostatic hyperplasia
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Contraindicated (0)
Serious - Use Alternative (17)
- 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
- buprenorphine, long-acting injection
buprenorphine, long-acting injection 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.
Adverse Effects
Varies in incidence & severity with the individual drug; also individual patients vary in susceptibility
Frequency Not Defined
CNS depression
Drowsiness
Sedation ranging from mild drowsiness to deep sleep (most frequent)
Dizziness
Lassitude
Disturbed coordination
Muscular weakness
Restlessness, insomnia, tremors, euphoria, nervousness, delirium, palpitation, seizures is less common
Epigastric distress
Anorexia
Nausea
Vomiting
Diarrhea
Constipation
Cholestasis, hepatitis, hepatic failure, hepatic function abnormality, jaundice is rare
Tachycardia, palpitation ECG changes (eg, widened QRS)
Arrhythmias (eg, extrasystole, heart block)
Hypotension
Hypertension
Dizziness, sedation, and hypotension may occur in geriatric patients
Dryness of mouth, nose, and throat
Dysuria
Urinary retention
Impotence
Vertigo
Visual disturbances
Blurred vision
Diplopia; tinnitus
Acute labyrinthitis
Insomnia
Tremors
Nervousness
Irritability
Facial dyskinesia
Tightness of the chest
Thickening of bronchial secretions
Wheezing
Nasal stuffiness
Sweating
Chills
Early menses
Toxic psychosis
Headache
Faintness
Paresthesia
Agranulocytosis
Hemolytic anemia
Leukopenia
Thrombocytopenia
Pancytopenia
Warnings
Contraindications
Documented hypersensitivity
Lower respiratory disease, eg, asthma (controversial)
Preemies & neonates
Nursing women
Acute asthma, sleep apnea
Cautions
Caution in narrow angle glaucoma, prostatic hypertrophy, stenosing peptic ulcer, pyloroduodenal obstruction, or bladder neck obstruction
Chlor Trimeton non-drowsy contains no chlorpheniramine, only pseudoephedrine
All injections discontinued
Pregnancy & Lactation
Pregnancy
Antihistamine exposure in first trimester not reported to be associated with increased risk of malformations; animal studies not reported; there are no controlled data in human pregnancy; only recommended for use during pregnancy when benefit outweighs risk
Lactation
Excretion into human milk; the manufacturer recommends that caution be used when administering chlorpheniramine to nursing women; infants should be monitored for irritability or drowsiness; antihistamines may temporarily decrease maternal serum prolactin concentrations when administered prior to nursing infant for the first time
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Histamine H1-receptor antagonist in blood vessels, respiratory tract, and gastrointestinal tract
Pharmacokinetics
Half-Life elimination: 10-13 hr (children); 14-24hr (adult)
Duration: 24 hr
Peak Plasma Time: 2-3 hr (range 1-6 hr)
Protein Bound: 29-37%
Vd: 4-7 L/kg (children); 6-12 L/kg (adults)
Metabolism: Liver (CYP2D6)
Metabolites: Monodesmethylchlorpheniramine, didesmethylchlorpheniramine
Excretion: Urine
Sedative effect: Low
Antihistamine activity: Moderate
Anticholinergic acitivity: Moderate
Administration
Parenteral forms discontinued
IV Compatibilities
Additive: amikacin, calcium chloride, kanamycin, norepinephrine, pentobarbital
Syringe: diatrizoate meglumine, diatrizoate sodium, iodipamide meglumine, iothalamate meglumine, iothalamate sodium
IV/IM Administration
Administer SC/IM/IV injection over 1 min
100 mg/mL injection should not be given IV
Storage
Store at 25C
Protect from light
