European Journal of Clinical Pharmacology

, Volume 11, Issue 3, pp 193-198

First online:

Agranulocytosis during treatment with clozapine

  • J. Idänpään-HeikkiläAffiliated withNational Board of Health
  • , E. AlhavaAffiliated withNational Board of Health
  • , M. OlkinuoraAffiliated withNational Board of Health
  • , I. P. PalvaAffiliated withNational Board of Health

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Within six months of the introduction of the new antipsychotic drug clozapine in Finland, 17 cases of neutropenia or agranulocytosis were recorded amongst about 3000 patients treated. Agranulocytosis was fatal in eight patients, and in addition, two patients developed thrombocytopenia, and one patient leukaemia. As additional cases might well have been overlooked as banal infections, the risk of developing agranulocytosis during clozapine treatment was at least 0.5%. Impaired elimination of the drug or increased susceptibility of granulocyte precursors to clozapine, possibly due to some inherited characteristic, might explain the high incidence of complications.

Key words

clozapine agranulocytosis adverse reaction side effect haematological effect psychopharmacological agent neuroleptics