Drowsiness, fatigue, headache, blurred vision, vomiting and dry mouth are common side effects of meclizine, states RxList. More serious side effects that the patient should report to her doctor include mood changes, fast or irregular heartbeat, urinary difficulties, and tremors. Seizures or allergic reactions are possible side effects as well and require immediate medical attention. Signs and symptoms of allergic reactions include severe dizziness, breathing difficulty, rash, and itching or swelling, especially swelling of the face, tongue or throat.
Topical antihistamines, such as diphenhydramine creams, sprays or ointments, may interact with meclizine, warns WebMD. Before taking meclizine, the individual should tell her doctor if she takes other medications that may cause drowsiness, such as other antihistamines, drugs that treat anxiety or promote sleep, muscle relaxants, and narcotic pain relievers, because combining these medications with meclizine can intensify the drowsiness. This drowsiness also means that driving and operating heavy machinery while taking it are contraindicated, notes RxList. Individuals should not drink alcohol while taking meclizine.
Meclizine is an oral antihistamine that prevents and treats symptoms of motion sickness, such as nausea, vomiting and dizziness, reports RxList. Doctors also prescribe it to treat effects of inner ear diseases, such as vertigo, lightheadedness and dizziness.