Agranulocytosis associated with aprindine and other antiarrhythmic drugs: an epidemiological approach.

The risk of agranulocytosis associated with anti-arrhythmic drugs has been assessed by studying previous drug exposure of all cases collected through a multicentre surveillance network in a defined geographical area during the period 1980-1988. One hundred and eighty-one patients with agranulocytosis (less than 500 granulocytes mm-3 at least in two different blood counts) were interviewed with a structured questionnaire. Eight cases attributable to anti-arrhythmic drugs were identified, all of them related to aprindine. Data on the consumption of several anti-arrhythmic drugs were identified, all of them related to aprindine. Data on the consumption of several anti-arrhythmic drugs (amiodarone, aprindine, quinidine, propafenone) were obtained in order to estimate the risk of agranulocytosis related with the previous use of these drugs. A relevant risk was identified only for aprindine, of the order of two cases per 1000 patient-years. Our data suggest that the risk of agranulocytosis associated with aprindine is lower than previously found.