Date - 27 May 2005

Source- Drugs in Context 2005; 1(7): Olanzapine - Bipolar disorder p413

Author - Dr Eleanor Bull

Olanzapine is an atypical antipsychotic indicated for the acute and maintenance treatment of bipolar disorder. This includes the short-term treatment of moderate-to-severe manic episodes and long-term prophylaxis for the prevention of both manic and depressive relapse. Olanzapine displays a broad pharmacological profile with high affinity across a range of neuronal receptors. In common with other atypical antipsychotics, olanzapine shows high mesolimbic and mesocortical selectivity with little effect on the nigrostriatal pathway. Controlled clinical studies examining the effectiveness of olanzapine in the treatment of acute mania, have clearly demonstrated its superiority over placebo, with a significant proportion of olanzapine-treated patients undergoing symptomatic remission as early as 3 weeks after treatment initiation. Olanzapine is generally more effective than valproate and as effective as haloperidol in terms of response and remission rates in patients with acute mania. Furthermore, patients with a history of rapid-cycling bipolar disorder also respond well to acute treatment with olanzapine, though their response to longer-term therapy appears to be less pronounced. Long-term studies have shown that the short-term improvements associated with olanzapine can be maintained for up to 18 months after treatment initiation. Using olanzapine in combination with a mood-stabilising agent has been shown to provide additional efficacy compared with use of lithium or valproate alone, with patients experiencing only minor increases in adverse events. The incidence of extrapyramidal symptoms (EPS) following olanzapine is lower than that reported following treatment with typical antipsychotics.

Keywords: Bipolar disorder, olanzapine, atypical antipsychotics, mania. EPS