Agranulocytosis and clozapine

BMJ 1994;309:54 (2 July)

Letters

Agranulocytosis and clozapine

EDITOR, - In his editorial on the use of risperidone in schizophreniaJ Guy Edwards remarks that agranulocytosis is "such a problemwith clozapine."¹ This merits comment.

Clozapine is sold by Sandoz Pharmaceuticals under the tradenames Clozaril and Leponex. After postmarketing experience inFinland in 1975 Sandoz addressed the problem of agranulocytosispromptly by installing a worldwide haematological monitoringsystem for patients who were prescribed the two products. Oneof the basic requirements of this system is a normal leucocyteand differential cell counts before treatment with clozapineis started, followed by blood counts performed at least oncea week for the first 18 weeks and at least monthly thereafter.Our experience has shown that 85% of cases of agranulocytosisoccur during the first 18 weeks of treatment. Clozapine is stoppedimmediately and permanently in patients who develop leucopeniaor granulocytopenia. A "no blood, no drug" policy ensures that. . . [Full text of this article]