Trecetilide is a class III antiarrhythmic agent developed for the treatment of atrial flutter and fibrillation. Trecetilide probably has effects on the cardiac myocyte membrane that are similar to ibutilide. It is being developed for both oral and intravenous administration. Unlike ibutilide, trecetilide has good oral bioavailability. Trecetilide has a good metabolic stability. As with ibutilide, its mechanism of class III action may involve both rectifier K+ current blockade and other mechanisms of prolonging repolarization.