Review of olanzapine in the management of bipolar disorders

Olanzapine is an atypical antipsychotic currently with indications for the treatment of schizophrenia, acute mania and the prevention of relapse in bipolar disorder. A growing body of clinical evidence supports these indications. Acute mania trials have demonstrated superior efficacy of olanzapine to placebo, equal or superior efficacy to valproate and superior efficacy in combination therapy with lithium or valproate compared to mood stabilizer monotherapy. Olanzapine demonstrated a modest effect in the treatment of bipolar depression with a substantially enhanced effect in combination with fluoxetine. Maintenance trials showed olanzapine to be more efficacious than placebo in the prevention of manic and depressive relapses and non-inferior to lithium or valproate. Combination of olanzapine with lithium or valproate was also found to be more efficacious than lithium or valproate monotherapy in the prevention of manic relapse in patients with a partial response to monotherapy with lithium or valproate. These trials suggest that olanzapine is a viable option and an invaluable addition to the pharmacological armamentarium in the treatment of bipolar I disorder. However, this can often be mitigated by safety and tolerability concerns with this agent including weight gain and metabolic syndrome that warrants clinician vigilance and discernment that is imperative in today's clinical practice.