If you are using the over-the-counter product, read all directions on the product package before using this medication. If your doctor has prescribed this medication, use it exactly as directed.

Use this medication in the affected eye(s) as directed by the product package or by your doctor, usually twice a day (every 8 to 12 hours).

Dosage is based on your medical condition and response to treatment.

To apply eye drops, wash your hands first. To avoid contamination, do not touch the dropper tip or let it touch your eye or any other surface.

Ask your doctor if you can wear contact lenses while you are being treated with this medication. If your doctor says you may continue wearing them, remove them before using the eye drops, and wait at least 10 minutes after each dose before putting in your lenses. Do not use this medication to treat irritation from contact lens wear. Consult your doctor about the use of contact lenses when the eyes are red or irritated.

Tilt your head back, look upward, and pull down the lower eyelid to make a pouch. Hold the dropper directly over your eye and apply 1 drop in the lower eyelid. Look downward and gently close your eyes for 1 to 2 minutes. Place one finger at the corner of your eye (near the nose) and apply gentle pressure. This will prevent the medication from draining out. Try not to blink and do not rub your eye.

Do not rinse the dropper. Replace the dropper cap after each use, and keep the bottle tightly closed.

If you are using another kind of eye medication (drops or ointment), wait at least 5 minutes before applying it. Apply eye drops before eye ointments to allow the eye drops to enter the eye.

Wait several minutes for your vision to clear before driving or operating machinery.

If your doctor has prescribed this medication, use it regularly in order to get the most benefit from it. To help you remember, use it at the same times each day. Continue to use this medication as prescribed until pollen season is over or you are no longer exposed to the allergic substance, even when allergic symptoms disappear or improve.

If your condition lasts or gets worse, if you develop new symptoms, or if you think you have a serious medical problem, get medical help right away. If you are treating yourself with nonprescription ketotifen, tell your doctor if your itching gets worse or lasts more than 72 hours. You may need a different medication.