Drug information of chlorcyclizine

chlorcyclizine

Drug group: Antihistamine

Chlorcyclizine is an antihistamine that reduces the effects of natural chemical histamine in the body. Histamine can produce symptoms of sneezing, itching, watery eyes, and runny nose.
Chlorcyclizine and pseudoephedrine is a combination medicine used to treat runny or stuffy nose, sneezing, itching, watery eyes, sinus congestion, and other cold or allergy symptoms.

Mechanism of effect

antagonist for Histamin H1 reseptores in human

Pharmacodynamic

Not available.

Pharmacokinetics

absorption: Readily absorbed after oral administration and widely distributed throughout the body. Metabolised by N-demethylation to form norchlorcyclizine and by N-oxidation.
volume of distribution: After a single oral dose of 2 mg/kg to 4 subjects, average peak plasma concentrations of about 0.05 mg/L and 0.03 mg/L were attained in 5 h for unchanged drug and norchlorcyclizine, respectively. After oral administration of 50 mg 3 times a day for 6 days, plasma concentrations of norchlorcyclizine of 0.05 to 0.11 mg/L were reported on the first day after the cessation of treatment and plasma concentrations of 0.02 to 0.04 mg/L were found on the 10th day after cessation of treatment [Kuntzman et al. 1973].
protein binding: about 85 to 90%.
metabolism: High concentrations of the N-desmethyl metabolite are found in the liver, lungs, kidney, and spleen.
Route of elimination: Slowly excreted in the urine; measurable amounts of norchlorcyclizine have been detected in the urine for up to 3 weeks after the cessation of chronic oral administration. About 0.5% of a single dose is excreted in the urine as the N-oxide.
Half-life: about 12 h.

Drug indications

nasal stuffiness

Dosage

Usual Adult Dose for Nasal Congestion
Chlorcyclizine-pseudoephedrine 25 mg-60 mg oral tablet:
1 tablet orally every 6 to 8 hours not to exceed 3 tablets daily.
Chlorcyclizine-pseudoephedrine 9.375 mg-30 mg/5 mL oral liquid:
10 mL orally every 6 hours not to exceed 40 mL daily.
Usual Pediatric Dose for Nasal Congestion
Chlorcyclizine-pseudoephedrine 25 mg-60 mg oral tablet:
6 to 11 years: 1/2 tablet orally every 6 to 8 hours not to exceed 1 1/2 tablets daily.
12 years or older: 1 tablet orally every 6 to 8 hours not to exceed 3 tablets daily.
Chlorcyclizine-pseudoephedrine 9.375 mg-30 mg/5 mL oral liquid:
6 to 11 years: 5 mL orally every 6 hours not to exceed 20 mL daily.
12 years or older: 10 mL orally every 6 hours not to exceed 40 mL daily.

Pregnancy level

Requires a Risk/Benefit Assessment

Breast feeding warning

Moderately safe.

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