zafirlukast

Zafirlukast

Zafirlukast is an orally administered leukotriene receptor antagonist (LTRA) used for the chronic treatment of asthma. While zafirlukast is generally well tolerated, headaches and stomach upset often occur. Some rare side effects can occur, which can be life-threatening, such as liver failure. Eosinophilic granulomatosis with polyangiitis has been associated with zafirlukast, but the relationship is not thought to be causative. Overdoses of zafirlukast tend to be self-limiting. Zafirlukast, like other LTRAs, works by inhibiting the immune system. Through its action on inflammatory cells in the lungs, zafirlukast reduces the production of inflammatory mediators that are implicated in the disease process of asthma. Zafirlukast is extensively hepatically metabolized by an enzyme called CYP2C9. Zafirlukast inhibits the action of CYP3A4, leading to drug-drug interactions with other drugs that are metabolized by CYP3A4. Genetic differences in LTC4 synthase and CYP2C9 may predict how a person reacts to zafirlukast treatment. Zafirlukast (brand name Accolate) was the first cysteinyl leukotriene receptor antagonist approved in the United States. It is now approved in other countries under various brand names.