Meclizine Hydrocloride

Clinical summary

Indications and usage 1 INDICATIONS AND USAGE Meclizine hydrochloride is indicated for the treatment of vertigo associated with diseases affecting the vestibular system in adults. Meclizine hydrochloride is indicated for the treatment of vertigo associated with diseases affecting the vestibular system in adults ( 1 ). Dosage and administration 2 DOSAGE AND ADMINISTRATION Recommended dosage: 25 mg to 100 mg daily, in divided doses ( 2.1 ). Tablets: Swallow whole ( 2.2 ). 2.1 Recommended Dosage The recommended dosage is 25 mg to 100 mg daily administered orally, in divided doses, depending upon clinical response. 2.2 Administration Instructions Tablets Meclizine hydrochloride tablets must be swallowed whole. Warnings and cautions 5 WARNINGS AND PRECAUTIONS May cause drowsiness: Use caution when driving a car or operating dangerous machinery ( 5.1 ). Potential anticholinergic action: this drug should be prescribed with care to patients with a history of asthma, glaucoma, or enlargement of the prostate gland ( 5.2 ). 5.1 Drowsiness Since drowsiness may occur with use of meclizine hydrochloride, patients should be warned of this possibility and cautioned against driving a car or operating dangerous machinery. Patients should avoid alcoholic beverages while taking meclizine hydrochloride [see Drug Interactions (7.1) ]. 5.2 Concurrent Medical Conditions Because of its potential anticholinergic action, meclizine hydrochloride should be used with caution in patients with asthma, glaucoma, or enlargement of the prostate gland. Drug interactions 7 DRUG INTERACTIONS Coadministration of Meclizine hydrochloride with other CNS depressants, including alcohol, may result in increased CNS depression ( 7.1 ). CYP2D6 inhibitors: As meclizine is metabolized by CYP2D6, there is a potential for drug-drug interactions between Meclizine hydrochloride and CYP2D6 inhibitors ( 7.2 ). 7.1 CNS Depressants There may be increased CNS depression when meclizine hydrochloride is administered concurrently with other CNS depressants, including alcohol [see Warnings and Precautions (5.1) ]. 7.2 CYP2D6 Inhibitors Based on in-vitro evaluation, meclizine is metabolized by CYP2D6. Therefore, there is a possibility for a drug interaction between meclizine hydrochloride and CYP2D6 inhibitors. Therefore, monitor for adverse reactions and clinical effect accordingly. Pregnancy 8.1 Pregnancy Risk Summary Data from epidemiological studies have not generally indicated a drug-associated risk of major birth defects with meclizine during pregnancy. However, in a published study, an increased incidence of fetal malformations was observed following oral administration of meclizine to pregnant rats during the period of organogenesis, at doses similar to those used clinically. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. The background risk of major birth defects and miscarriage for the indicated population is unknown. Data Human Data Epidemiological studies reporting on pregnancies exposed to meclizine have not identified an association between the use of meclizine during pregnancy and an increased risk of major birth defects. Animal Data In a published study, oral administration of meclizine (25-250 mg/kg) to pregnant rats during the period of organogenesis resulted in a high incidence of fetal malformations. These effects occurred at doses as low as 25 mg/kg, which is approximately 2 times the maximum recommended human dose (100 mg) on a body surface area (mg/m 2 ) basis.