Cyclizine is an antihistamine that is used to prevent and treat nausea, vomiting, or dizziness caused by motion sickness. It works by blocking a chemical called histamine in the brain that can make you feel sick. Cyclizine is also used to treat morning sickness, vertigo, and sickness caused by general anesthesia after surgery, cancer treatment, or other medicines, and some inner ear problems such as Ménières disease. It is available on prescription and to buy from pharmacies in the form of tablets and injections. Cyclizine starts to work about 30 minutes after taking it, and you should feel better after 1 to 2 hours. Common side effects include feeling sleepy and blurred vision. Cyclizine should not be taken with alcohol, as it increases the risk of side effects. If you miss a dose, take it as soon as you can. If it is almost time for your next dose, take only that dose. Do not take double or extra doses.