Olopatadine is an antihistamine that reduces the natural chemical histamine in the body. Histamine can produce symptoms of itching or watery eyes.

Pataday Twice A Day Relief (for the eye) is used to treat eye itching caused by allergies.

Pataday Twice A Day Relief may also be used for purposes not listed in this medication guide.

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

Use exactly as directed on the label, or as prescribed by your doctor.

Do not use while wearing soft contact lenses. A preservative in this medicine could permanently stain the lenses. Use the medicine at least 15 minutes before inserting your contact lenses.

Wash your hands before using eye medication.

To apply the eye drops: Tilt your head back slightly and pull down your lower eyelid to create a small pocket. Hold the dropper above the eye and squeeze a drop into this pocket. Close your eyes for 1 or 2 minutes.

• Wait at least 10 minutes before using any other eye drops your doctor has prescribed.

Use only the number of drops recommended on the medicine label.

Do not touch the tip of the eye dropper or place it directly on your eye. A contaminated dropper can infect your eye, which could lead to serious vision problems.

Do not use the eye drops if the liquid looks cloudy or has changed colors.

Store at room temperature away from moisture and heat. Do not freeze. Keep the bottle tightly closed when not in use.

You should not use Pataday Twice A Day Relief if you are allergic to it.

Ask a doctor or pharmacist if Pataday Twice A Day Relief is safe to use if you have any type of eye infection.

Tell your doctor if you are pregnant or breastfeeding.

Pataday Twice A Day Relief is not approved for use by anyone younger than 2 years old.

Use the medicine as soon as you can, but skip the missed dose if it is almost time for your next dose. Do not use two doses at one time.

An overdose of Pataday Twice A Day Relief is not expected to be dangerous. Seek emergency medical attention or call the Poison Help line at 1-800-222-1222 if anyone has accidentally swallowed the medication.

Avoid wearing contact lenses while your eyes are red or irritated. Pataday Twice A Day Relief will not treat eye irritation caused by wearing contacts.

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

Pataday Twice A Day Relief may cause serious side effects. Stop using Pataday Twice A Day Relief and call your doctor at once if you have:

• eye pain or changes in vision;

• eye itching that gets worse or lasts longer than 72 hours;

• severe burning, stinging, or irritation after using this medicine; or

• eye swelling, redness, severe discomfort, crusting or drainage (may be signs of infection).

Less serious side effects may be more likely, and you may have none at all.

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.