Psychopharmacology of olanzapine

The development of atypical antipsychotics has revolutionised the treatment of schizophrenia, as well as providing new insights into its cause. The archetypal atypical antipsychotic is clozapine, which has therapeutic advantages over traditional antipsychotics, as well as a low potential for producing extrapyramidal side-effects (EPS) (Kane et al, 1988). However, clozapine causes agranulocytosis in 1% of patients, and there has consequently been a search for novel atypical antipsychotics, as efficacious as clozapine, but without the need for intensive blood monitoring. There has been much discussion of the definition and characteristics of an atypical antipsychotic drug, and an operational understanding seems to have been agreed upon, that atypical drugs have therapeutic efficacy in treating schizophrenia, without producing EPS (Deutch et al, 1991; Kerwin, 1994).