Ketotifen

Ketotifen is a second-generation noncompetitive H₁-antihistamine and mast cell stabilizer. It is most commonly sold as a salt of fumaric acid, ketotifen fumarate, and is available in two forms. In its ophthalmic form, it is used to treat allergic conjunctivitis, or the itchy red eyes caused by allergies. In its oral form, it is used to prevent asthma attacks. Side effects include drowsiness, weight gain, dry mouth, irritability, and increased nosebleeds.