Propafenone associated agranulocytosis.

Propafenone hydrochloride was approved for marketing by the United States (U.S.) Food and Drug Administration (FDA) in November 1989. During U.S. clinical trials of propafenone, one case of agranulocytosis was seen. Seven additional cases have been reported outside the U.S. One German report of profound but reversible granulocytopenia appeared in 1982. In January 1991, the FDA reviewed adverse events reported with propafenone. Four reports of agranulocytosis were identified and are described. The reporting rate of approximately one case of agranulocytosis per 10,000 propafenone prescriptions per year likely underestimates the true incidence of this adverse event.