Page 2: Cardinal Health: Management of nausea and vomiting, and dizziness associated with motion sickness. CONTRAINDICATIONS: Meclizine HCl USP is. Inactive ingredients include: colloidal silicon dioxide, lactose monohydrate, magnesium stearate, microcrystalline cellulose, sodium starch glycolate and talc. CONTRAINDICATIONS. Meclizine hydrochloride is contraindicated in individuals who have shown a previous hypersensitivity to it. WARNINGS. 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. As meclizine undergoes metabolism, hepatic impairment may result in increased systemic exposure of the drug. 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. Treatment with meclizine should be administered with caution in patients with hepatic impairment. Meclizine hydrochloride, an oral antiemetic, is a white, slightly yellowish, crystalline powder which has a slight odor and is tasteless. It has the following structural formula: Meclizine hydrochloride is an antihistamine that shows marked protective activity against nebulized histamine and lethal doses of intravenously injected histamine in guinea pigs. Usual Dosage: See package insert for full prescribing information. MOTION SICKNESS: 25 mg to 50 mg daily. Store at 20° to 25°C (68° to 77°F);. Meclizine Hydrochloride Drug Information from Drugs.com. Includes Meclizine Hydrochloride side effects, interactions and indications. meclizine increases the risk of abnormalities when administered during pregnancy. Despite the Despite the animal findings, it would appear that the possibility of fetal harm is remote.