Dosing & Uses
Dosage Forms & Strengths
acetaminophen/chlorpheniramine
tablet
- 325mg/2mg
Relief of Cold & Flu Symptoms
2 tablets PO q4hr
Hepatic Impairment
May tolerate low dose therapy but use caution; cases of hepatotoxicity at doses < 4 g/day reported
Dosage Forms & Strengths
acetaminophen/chlorpheniramine
tablet
- 325mg/2mg
Relief of Cold & Flu Symptoms
≥12 years: 2 tablets PO q4hr
Interactions
Interaction Checker
No Results
Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor
Contraindicated (0)
Serious - Use Alternative (20)
- 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.
- fentanyl
fentanyl and chlorpheniramine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate
- fentanyl intranasal
fentanyl intranasal and chlorpheniramine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate
- fentanyl iontophoretic transdermal system
fentanyl iontophoretic transdermal system and chlorpheniramine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate
- fentanyl transdermal
fentanyl transdermal and chlorpheniramine both increase sedation. Avoid or Use Alternate Drug. Limit use to patients for whom alternative treatment options are inadequate
- 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
acetaminophen will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of lonafarnib (a sensitive CYP3A substrate) with weak CYP3A inhibitors is unavoidable, reduce to, or continue lonafarnib at starting dose. Closely monitor for arrhythmias and events (eg, syncope, heart palpitations) since lonafarnib effect on QT interval is unknown.
lonafarnib will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with sensitive CYP3A substrates. If coadministration unavoidable, monitor for adverse reactions and reduce CYP3A substrate dose in accordance with product labeling. - 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.
- pexidartinib
acetaminophen and pexidartinib both increase Other (see comment). Avoid or Use Alternate Drug. Pexidartinib can cause hepatotoxicity. Avoid coadministration of pexidartinib with other products know to cause hepatoxicity.
- 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.
- pretomanid
acetaminophen, pretomanid. Either increases toxicity of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Pretomanid regimen associated with hepatotoxicity. Avoid alcohol and hepatotoxic agents, including herbal supplements and drugs other than bedaquiline and linezolid.
- 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.
Monitor Closely (239)
- 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.
- apalutamide
apalutamide will decrease the level or effect of acetaminophen by increasing elimination. Use Caution/Monitor. Apalutamide induces UGT and may decrease systemic exposure of drugs that are UGT substrates.
- apomorphine
chlorpheniramine and apomorphine both increase sedation. Use Caution/Monitor.
- arformoterol
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.
- atogepant
acetaminophen will increase the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- avapritinib
acetaminophen will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
avapritinib and chlorpheniramine both increase sedation. Use Caution/Monitor. - axitinib
acetaminophen increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- azelastine
azelastine and chlorpheniramine both increase sedation. Use Caution/Monitor.
- 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.
- bupivacaine implant
acetaminophen, bupivacaine implant. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Local anesthetics may increase the risk of developing methemoglobinemia when concurrently exposed to drugs that also cause methemoglobinemia.
- buprenorphine
chlorpheniramine and buprenorphine both increase sedation. Use Caution/Monitor.
- buprenorphine buccal
chlorpheniramine and buprenorphine buccal both increase sedation. Use Caution/Monitor.
- busulfan
acetaminophen increases levels of busulfan by decreasing metabolism. Use Caution/Monitor. Use of acetaminophen prior to (< 72 hours) or concurrently with busulfan may result in decreased clearance of busulfan due to acetaminophen-induced decreases in glutathione levels.
- butabarbital
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.
- dapsone topical
acetaminophen increases toxicity of dapsone topical by altering metabolism. Modify Therapy/Monitor Closely. May induce methemoglobinemia .
- 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.
- eltrombopag
eltrombopag increases levels of acetaminophen by decreasing metabolism. Use Caution/Monitor. UGT inhibition; significance of interaction unclear.
- elvitegravir/cobicistat/emtricitabine/tenofovir DF
elvitegravir/cobicistat/emtricitabine/tenofovir DF increases levels of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. CYP3A4 substrates for which elevated plasma concentrations are associated with serious and/or life-threatening events.
- ephedrine
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.
- exenatide injectable solution
exenatide injectable solution will decrease the level or effect of acetaminophen by unspecified interaction mechanism. Use Caution/Monitor. To avoid potential interaction, give acetaminophen at least 1 hour before or 4 hours after exenatide injection.
- exenatide injectable suspension
exenatide injectable suspension will decrease the level or effect of acetaminophen by unspecified interaction mechanism. Use Caution/Monitor. To avoid potential interaction, give acetaminophen at least 1 hour before or 4 hours after exenatide injection.
- fedratinib
fedratinib will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.
- fenfluramine
chlorpheniramine increases and fenfluramine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- fentanyl
fentanyl, chlorpheniramine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with anticholinergics may increase risk for urinary retention and/or severe constipation, which may lead to paralytic ileus.
- fentanyl intranasal
fentanyl intranasal, chlorpheniramine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with anticholinergics may increase risk for urinary retention and/or severe constipation, which may lead to paralytic ileus.
- fentanyl transdermal
fentanyl transdermal, chlorpheniramine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with anticholinergics may increase risk for urinary retention and/or severe constipation, which may lead to paralytic ileus.
- fentanyl transmucosal
fentanyl transmucosal, chlorpheniramine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with anticholinergics may increase risk for urinary retention and/or severe constipation, which may lead to paralytic ileus.
- finerenone
acetaminophen will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or moderate CYP3A4 inhibitors. Adjust finererone dosage as needed.
- flibanserin
chlorpheniramine and flibanserin both increase sedation. Modify Therapy/Monitor Closely. Risk for sedation increased if flibanserin is coadministration with other CNS depressants.
acetaminophen will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased flibanserin adverse effects may occur if coadministered with multiple weak CYP3A4 inhibitors. - fluphenazine
chlorpheniramine and fluphenazine both increase sedation. Use Caution/Monitor.
- imatinib
imatinib decreases levels of acetaminophen by decreasing hepatic clearance. Modify Therapy/Monitor Closely. In vitro, imatinib was found to inhibit acetaminophen O-glucuronidation (Ki value of 58.5 micro-M) at therapeutic levels; avoid chronic acetaminophen therapy with imatinib; if occasional acetaminophen administered, do not exceed 1300 mg/day.
- flurazepam
chlorpheniramine and flurazepam both increase sedation. Use Caution/Monitor.
- 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.
- isavuconazonium sulfate
acetaminophen will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- isoniazid
isoniazid will increase the level or effect of acetaminophen by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.
- isoproterenol
chlorpheniramine increases and isoproterenol decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- istradefylline
istradefylline will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.
- ivacaftor
acetaminophen increases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor when coadministered with weak CYP3A4 inhibitors .
- kava
kava increases effects of chlorpheniramine by pharmacodynamic synergism. Use Caution/Monitor. May enhance CNS depression.
- ketamine
ketamine and chlorpheniramine both increase sedation. Use Caution/Monitor.
- ketotifen, ophthalmic
chlorpheniramine and ketotifen, ophthalmic both increase sedation. Use Caution/Monitor.
- lasmiditan
lasmiditan, chlorpheniramine. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.
- lemborexant
acetaminophen will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Lower nightly dose of lemborexant recommended if coadministered with weak CYP3A4 inhibitors. See drug monograph for specific dosage modification.
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.
- levonorgestrel oral/ethinylestradiol/ferrous bisglycinate
levonorgestrel oral/ethinylestradiol/ferrous bisglycinate will decrease the level or effect of acetaminophen by unknown mechanism. Use Caution/Monitor.
acetaminophen increases levels of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by decreasing hepatic clearance. Use Caution/Monitor. Coadministration of ascorbic acid and certain combined hormonal contraceptives (CHCs) containing EE may increase plasma EE concentrations, possibly by inhibition of conjugation. - 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.
- lixisenatide (DSC)
lixisenatide (DSC) will decrease the level or effect of acetaminophen by inhibition of GI absorption. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. GLP1 agonists delay gastric emptying, which may affect absorption of concomitantly administered oral medications. No effects on acetaminophen Cmax and Tmax were observed when acetaminophen was administered 1 hr before lixisenatide. When administered 1 or 4 hr after lixisenatide, acetaminophen Cmax was decreased by 29% and 31% respectively and median Tmax was delayed by 2 and 1.75 hr, respectively.
- lofepramine
chlorpheniramine and lofepramine both increase sedation. Use Caution/Monitor.
- lofexidine
chlorpheniramine and lofexidine both increase sedation. Use Caution/Monitor.
- lomitapide
acetaminophen increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Lomitapide dose should not exceed 30 mg/day.
- loprazolam
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.
acetaminophen will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of mild CYP3A4 inhibitors with midazolam intranasal may cause higher midazolam systemic exposure, which may prolong sedation. - midodrine
chlorpheniramine increases and midodrine decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
- mipomersen
mipomersen, acetaminophen. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Both drugs have potential to increase hepatic enzymes; monitor LFTs.
- 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
acetaminophen will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
tazemetostat will decrease the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. - 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.
- tetracaine
tetracaine, acetaminophen. Other (see comment). Use Caution/Monitor. Comment: Monitor for signs of methemoglobinemia when methemoglobin-inducing drugs are 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.
- tinidazole
acetaminophen will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- topiramate
chlorpheniramine and topiramate both increase sedation. Modify Therapy/Monitor Closely.
- 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.
- warfarin
acetaminophen increases effects of warfarin by anticoagulation. Use Caution/Monitor.
- xylometazoline
chlorpheniramine increases and xylometazoline decreases sedation. Effect of interaction is not clear, use caution. Use Caution/Monitor.
Minor (57)
- acetazolamide
acetazolamide will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
acetazolamide decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites. - albiglutide
albiglutide decreases levels of acetaminophen by unspecified interaction mechanism. Minor/Significance Unknown.
- anastrozole
anastrozole will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- antithrombin alfa
acetaminophen increases effects of antithrombin alfa by unknown mechanism. Minor/Significance Unknown.
- antithrombin III
acetaminophen increases effects of antithrombin III by unknown mechanism. Minor/Significance Unknown.
- argatroban
acetaminophen increases effects of argatroban by unknown mechanism. Minor/Significance Unknown.
- ashwagandha
ashwagandha increases effects of chlorpheniramine by pharmacodynamic synergism. Minor/Significance Unknown. May enhance CNS depression.
- bemiparin
acetaminophen increases effects of bemiparin by unknown mechanism. Minor/Significance Unknown.
- bivalirudin
acetaminophen increases effects of bivalirudin by unknown mechanism. Minor/Significance Unknown.
- brimonidine
brimonidine increases effects of chlorpheniramine by pharmacodynamic synergism. Minor/Significance Unknown. Increased CNS depression.
- carbamazepine
carbamazepine decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- cholestyramine
cholestyramine decreases levels of acetaminophen by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- clonazepam
clonazepam decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- colestipol
colestipol decreases levels of acetaminophen by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- cyclophosphamide
cyclophosphamide will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- dalteparin
acetaminophen increases effects of dalteparin by unknown mechanism. Minor/Significance Unknown.
- diazepam
diazepam decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- disulfiram
disulfiram will increase the level or effect of acetaminophen by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.
- enoxaparin
acetaminophen increases effects of enoxaparin by unknown mechanism. Minor/Significance Unknown.
- ethanol
ethanol will decrease the level or effect of acetaminophen by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.
ethanol increases toxicity of acetaminophen by decreasing metabolism. Minor/Significance Unknown. - ethosuximide
ethosuximide decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- eucalyptus
chlorpheniramine and eucalyptus both increase sedation. Minor/Significance Unknown.
- felbamate
felbamate decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- fondaparinux
acetaminophen increases effects of fondaparinux by unknown mechanism. Minor/Significance Unknown.
- fosphenytoin
fosphenytoin decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- green tea
green tea increases effects of acetaminophen by pharmacodynamic synergism. Minor/Significance Unknown. (Theoretical, due to caffeine content).
- heparin
acetaminophen increases effects of heparin by unknown mechanism. Minor/Significance Unknown.
- isoniazid
isoniazid increases toxicity of acetaminophen by unknown mechanism. Minor/Significance Unknown.
- lacosamide
lacosamide decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- lamotrigine
lamotrigine decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- larotrectinib
larotrectinib will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- levetiracetam
levetiracetam decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- levoketoconazole
levoketoconazole will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- liraglutide
liraglutide decreases levels of acetaminophen by unspecified interaction mechanism. Minor/Significance Unknown.
- lorazepam
lorazepam decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- methsuximide
methsuximide decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- metoclopramide
metoclopramide increases levels of acetaminophen by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.
- metronidazole
metronidazole will increase the level or effect of acetaminophen by affecting hepatic enzyme CYP2E1 metabolism. Minor/Significance Unknown.
- nettle
nettle increases effects of chlorpheniramine by pharmacodynamic synergism. Minor/Significance Unknown. (High dose nettle; theoretical interaction) May enhance CNS depression.
- oxcarbazepine
oxcarbazepine decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- oxybutynin
oxybutynin decreases levels of acetaminophen by unspecified interaction mechanism. Minor/Significance Unknown.
- oxybutynin topical
oxybutynin topical decreases levels of acetaminophen by unspecified interaction mechanism. Minor/Significance Unknown.
- oxybutynin transdermal
oxybutynin transdermal decreases levels of acetaminophen by unspecified interaction mechanism. Minor/Significance Unknown.
- phenindione
acetaminophen increases effects of phenindione by unknown mechanism. Minor/Significance Unknown.
- phenobarbital
phenobarbital decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- phenytoin
phenytoin decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- primidone
primidone decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- protamine
acetaminophen increases effects of protamine by unknown mechanism. Minor/Significance Unknown.
- ribociclib
ribociclib will increase the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- rifabutin
rifabutin decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- rifampin
rifampin decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- rufinamide
rufinamide decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
- ruxolitinib
acetaminophen will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- ruxolitinib topical
acetaminophen will increase the level or effect of ruxolitinib topical 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.
- tiagabine
tiagabine decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
Adverse Effects
Frequency Not Defined
Hypotension
Palpitations
Tachycardia
Anxiety
Confusion
Depression
Dizziness
Drowsiness
Euphoria
Fatigue
Headache
Insomnia
Irritability
Nervousness
Tremors
Anorexia
Constipation
Diarrhea
Nausea
Vomiting
Agranulocytosis
Anemia
Blood dyscrasias (neutropenia, pancytopenia, leukopenia, thrombocytopenia)
Hemolytic anemia
Bilirubin and alkaline phosphatase may increase
Thickening of bronchial secretions
Wheezing
Dry mouth, nose, throat
Warnings
Contraindications
Hypersensitivity to drug or components
Cautions
This product contains acetaminophen. Severe liver damage may occur if adult takes more than 12 tablets in 24 hours, child takes more than 5 tablets in 24 hours, taken with other drugs containing acetaminophen, adult has 3 or more alcoholic drinks every day while using this product
Do not use with any other drug containing acetaminophen (prescription or non-prescription); if not sure whether a drug contains acetaminophen, ask a doctor pharmacist
User should ask a doctor before use if diagnosed with liver disease, a breathing problem such as emphysema or chronic bronchitis glaucoma trouble urinating due to an enlarged prostate gland
Ask a doctor or pharmacist before use if taking the blood thinning drug warfarin, taking sedatives or tranquilizers
When using this product excitability may occur, especially in children drowsiness may occur
Avoid alcoholic beverages
Alcohol, sedatives, and tranquilizers may increase drowsiness; use caution when driving a motor vehicle or operating machinery
Stop use and ask a doctor if pain gets worse or lasts more than 5 days (children 6 to under 12 years) or 10 days (adults)fever gets worse or lasts more than 3 days, redness or swelling is present, new symptoms occur
Pregnancy & Lactation
Pregnancy
Ask a health professional before use
Lactation
Ask a health professional before use
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
Chlorpheniramine blocks muscle responses in histamine and acts as an antagonism of the constrictor effects of histamine on respiratory smooth muscle.
Acetaminophen blocks pain impulse generation peripherally and may inhibit the generation of prostaglandin in the CNS. Reduces fever by inhibiting the hypothalamic heat-regulating center.
Pharmacokinetics
Chlorpheniramine
- Vd: 4-7 L/kg (children); 6-12 L/kg (adults)
- Protein binding: 33%
- Half-life: 10-13 hr (children); 14-24 hr (adults)
- Peak plasma time: 2-4 hr
- Excretion: Urine
Acetaminophen
- Peak plasma time: 10-60 min (PO immediate release); 60-120 min (PO extended release); 6 hr (PO 500 mg tablet); 8 hr (PO 650 mg extended release tablet)
- Vd: 1 L/kg
- Protein binding: 10-25%
- Metabolism: Liver (microsomal enzyme systems); conjugation (glucuronic acid)
- Half-life: 1.25-3hr
- Excretion: Urine
