Alcohol can intensify the sedative effects of meclizine, according to Drugs.com. When taken with alcohol, drowsiness and dizziness may be increased. Tasks that require alertness and fine motor skills should be avoided until the individual knows how the drug affects him.
Dry mouth, tiredness, drowsiness and blurred vision are the most common side effects of meclizine, states WebMD. Serious side effects include restlessness, confusion, a fast or irregular heartbeat, tremors, and difficulty urinating. Should these occur, contact a doctor immediately.
People with kidney or liver disease, breathing problems, glaucoma, heart problems, or high blood pressure should use meclizine with caution, reminds WebMD, and so should those with stomach or intestinal problems, an overactive thyroid, or difficult urination. Older adults and children may be more sensitive to the effects of the drug.
Antihistamines applied to the skin can interact with this medication, causing an overdose, notes WebMD. Drugs for sleep and anxiety, muscle relaxants, and narcotic pain relievers can cause additional sedation when used with meclizine. Check labels on nonprescription cold and allergy medications, as they may contain ingredients that increase drowsiness.
Meclizine is an antihistamine used to treat dizziness, nausea and vomiting associated with motion sickness, explains PDR Health. It is also used to treat the symptoms of vertigo.