Anti-itch drugs are medicines taken by mouth or by injection to relieve itching. The medicine described here, hydroxyzine, is a type of antihistamine used to relieve itching caused by allergic reactions. An allergic reaction occurs when the body is unusually sensitive to some substance, such as pollen, dust, mold, or certain foods or medicine. The body reacts by releasing a chemical called histamine that causes itching and other symptoms, such as sneezing and watery eyes. Antihistamines reduce the symptoms by blocking the effects of histamine.

Anti-itch drugs, also called antipruritic drugs, are available only with a physician's prescription and come in tablet and injectable forms. Some commonly used brands of the anti-itch drug hydroxyzine are Atarax and Vistaril. This medicine should not be used for more than four months at a time because its effects can wear off. See a physician regularly while taking the medicine to determine whether it is still needed.

Hydroxyzine may add to the effects of alcohol and other drugs that slow down the central nervous system, such as other antihistamines, cold medicine, allergy medicine, sleep aids, medicine for seizures, tranquilizers, some pain relievers, and muscle relaxants. Anyone taking hydroxyzine should not drink alcohol and should check with his or her physician before taking any other medicines.

Some people feel drowsy or less alert when using this medicine. Anyone who has had unusual reactions to hydroxyzine in the past should let his or her physician know before taking the medicine again. The physician should also be told about any allergies to foods, dyes, preservatives, or other substances.

A woman who is pregnant or who may become pregnant should check with her physician before taking this medicine. In studies of laboratory animals, hydroxyzine has caused birth defects when taken during pregnancy. Although the drug's effects on pregnant women have not been fully studied, physicians advise against taking it in early pregnancy. The medicine may pass into breast milk and may cause problems in nursing babies whose mothers take it.

The most common side effect, drowsiness, usually goes away as the body adjusts to the drug. If it does not, reducing the dosage may be necessary. Other side effects, such as dry mouth, also may occur and do not need medical attention unless they continue.

More serious side effects are not common, but may occur. Twitches, tremors, or convulsions (seizures) signal a need for medical attention.