Ketotifen, also known as Zaditor, is a second-generation noncompetitive H1-antihistamine and mast cell stabilizer. It is most commonly sold as a fumaric acid salt, ketotifen fumarate, and comes in two forms. It is used to treat allergic conjunctivitis in its ophthalmic form. It is used orally to prevent asthma attacks, anaphylaxis, and another mast cell, allergic-type disorders.
It was patented in 1970 and first used in medicine in 1976.
With over 1 million prescriptions in 2020, it was the 289th most commonly prescribed medication in the United States.
Ketotifen relieves and prevents the itching and irritation of the eyes caused by most seasonal allergies. It begins working immediately after the drops are administered. The medication has not been studied in children under the age of three. The average half-life of elimination is 12 hours. It is also a functional leukotriene antagonist and a phosphodiesterase inhibitor, in addition to its anti-histaminic activity.
