Zafirlukast

Zafirlukast is an oral medicine for the long-term treatment of asthma. It belongs to the leukotriene receptor antagonist family, which works by blocking the action of inflammatory chemical signals that the lungs produce in asthma, and it was the first drug of the cysteinyl leukotriene receptor antagonist type to be approved in the United States. It is sold under the brand name Accolate and under other brand names in other countries. Headaches and stomach upset are common and it is generally well tolerated, but rare serious effects such as liver failure are recorded, and an association with eosinophilic granulomatosis with polyangiitis has been noted without being judged causal. The body breaks it down mainly in the liver through the enzyme CYP2C9, and it inhibits CYP3A4, so it can interact with other drugs cleared by that enzyme.