Hydroxyzine reduces activity in the central nervous system. It also acts as an antihistamine that reduces the effects of natural chemical histamine in the body. Histamine can produce symptoms of itching, or hives on the skin.

Hydroxyzine is used as a sedative to treat anxiety and tension. It is also used together with other medications given during and after general anesthesia.

Hydroxyzine is also used to treat allergic skin reactions such as hives or contact dermatitis.

Hydroxyzine may also be used for purposes not listed in this medication guide.

You should not use hydroxyzine if you are allergic to it, or if:

• you have long QT syndrome;
• you are allergic to cetirizine (Zyrtec) or levocetirizine (Xyzal); or
• you are in the first trimester of pregnancy.

You should not use hydroxyzine if you are pregnant, especially during the first or second trimester. Hydroxyzine could harm the unborn baby or cause birth defects. Use effective birth control to prevent pregnancy while you are using this medicine.

To make sure hydroxyzine is safe for you, tell your doctor if you have:

• blockage in your digestive tract (stomach or intestines);
• bladder obstruction or other urination problems;
• glaucoma;
• heart disease, slow heartbeats;
• personal or family history of long QT syndrome;
• an electrolyte imbalance (such as high or low levels of potassium in your blood);
• if you have recently had a heart attack.

It is not known whether hydroxyzine passes into breast milk or if it could harm a nursing baby. You should not breast-feed while using this medicine.

Do not give this medicine to a child without medical advice.

Use Rezine (Oral) exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

In rare cases, hydroxyzine may cause a severe skin reaction. Stop taking this medicine and call your doctor right away if you have sudden skin redness or a rash that spreads and causes white or yellow pustules, blistering, or peeling.

Stop using hydroxyzine and call your doctor at once if you have:

• fast or pounding heartbeats;
• headache with chest pain;
• severe dizziness, fainting; or
• a seizure (convulsions).

Side effects such as drowsiness and confusion may be more likely in older adults.

Common side effects may include:

• drowsiness;
• headache;
• dry mouth; or
• skin rash.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

This medicine may impair your thinking or reactions. Be careful if you drive or do anything that requires you to be alert.

Drinking alcohol with this medicine can cause side effects.