HEMATOLOGICAL SAFETY OF ANTIPSYCHOTIC-DRUGS

Many clinicians have become concerned about the safety of new antipsyc hotics particularly in view of the association of agranulocytosis with clozapine and of aplastic anaemia with remoxipride. The Committee on Safety of Medicines and Medicines Control Agency 'yellow card' post-ma rketing surveillance data were analysed for reports of haemopoietic di sorders with the 16 antipsychotics in common use. Corrections for rela tive risk were made in three separate ways: (i) control for degree of use, using Northern Ireland prescribing data for 1995; (ii) percentage of total reports from 1963 to 1996; and (iii) examination of the firs t 5 years' post-marketing data only. After clozapine and remoxipride t he highest risks of haemopoietic reactions appeared to be associated w ith the aliphatic phenothiazine derivatives thioridazine and chlorprom azine. There is therefore no evidence of any increased risk with high- potency drugs such as haloperidol or pimozide or with the newer drugs such as sulpiride or risperidone. Continued vigilance, however, is nec essary as more new atypicals become available and begin to be widely p rescribed.