![]() ![]() (see WARNINGS).īased on in-vitro evaluation, meclizine is metabolized by CYP2D6. There may be increased CNS depression when meclizine is administered concurrently with other CNS depressants, including alcohol, tranquilizers, and sedatives. Due to a potential for drug/metabolite accumulation, meclizine should be administered with caution in patients with renal impairment and in the elderly as renal function generally declines with age. The effect of renal impairment on the pharmacokinetics of meclizine has not been evaluated. ![]() Treatment with meclizine should be administered with caution in patients with hepatic impairment. As meclizine undergoes metabolism, hepatic impairment may result in increased systemic exposure of the drug. ![]() The effect of hepatic impairment on the pharmacokinetic of meclizine has not been evaluated. Because many drugs are excreted in human milk, caution should be exercised when meclizine is administered to a nursing woman. It is not known whether this drug is excreted in human milk. Although the overall incidence of FD&C Yellow #5 (tartrazine) sensitivity in the general population is low, it is frequently seen in patients who also have aspirin hypersensitivity. The Meclizine Hydrochloride Tablets, 25mg contain FD&C Yellow #5 (tartrazine) which may cause allergic-type reactions (including bronchial asthma) in certain susceptible individuals. Nevertheless, meclizine, or any other medication, should be used during pregnancy only if clearly necessary. Despite the animal findings, it would appear that the possibility of fetal harm is remote. Epidemiological studies in pregnant women, however, do not indicate that meclizine increases the risk of abnormalities when administered during pregnancy. Reproduction studies in rats have shown cleft palates at 25 to 50 times the human dose. Due to its potential anticholinergic action, this drug should be used with caution in patients with asthma, glaucoma, or enlargement of the prostate gland.Ĭlinical studies establishing safety and effectiveness in children have not been done therefore, usage is not recommended in children under 12 years of age. Patients should avoid alcoholic beverages while taking the drug. Since drowsiness may, on occasion, occur with use of this drug, patients should be warned of this possibility and cautioned against driving a car or operating dangerous machinery. Meclizine has a plasma elimination half-life of about 5 to 6 hours in humans. The genetic polymorphism of CYP2D6 that results in extensive-, poor-,intermediate- and ultrarapid metabolizer phenotypes could contribute to large inter-individual variability in meclizine exposure. In an in vitro metabolic study using human hepatic microsome and recombinant CYP enzyme, CYP2D6 was found to be the dominant enzyme for metabolism of meclizine. The metabolic fate of meclizine in humans in unknown. Meclizine is absorbed after oral administration with maximum plasma concentrations reaching at a median Tmax value of 3 hours post-dose (range: 1.5 to 6 hours) for the tablet dosage form.ĭrug distribution characteristics for meclizine in humans in unknown. The available pharmacokinetic information for meclizine following oral administration has been summarized from published literature. Its activity is relatively weak in inhibiting the spasmogenic action of histamine on isolated guinea pig ileum. It has a marked effect in blocking the vasodepressor response to histamine, but only a slight blocking action against acetylcholine. Meclizine hydrochloride is an antihistamine which shows marked protective activity against nebulized histamine and lethal doses of intravenously injected histamine in guinea pigs. ![]()
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