Olanzapine: a review of rapid and long-acting parenteral formulations

Olanzapine, an atypical antipsychotic was first introduced in 1996 as an oral formulation and is used in the treatment of schizophrenia and bipolar disorder. Recent developments have included parenteral formulations to improve compliance in the treatment of schizophrenia and to treat agitation in patients with schizophrenia and bipolar mania. Olanzapine pamoate long acting injection (depot) is a novel formulation of the atypical antipsychotic olanzapine, which is licensed for the maintenance treatment of schizophrenia. When administered as the pamoate salt, olanzapine has an elimination half-life of approximately 30 days, allowing it to be given at 2- or 4-weekly intervals. An 8-week, randomized, double-blind study in 404 patients acutely ill with schizophrenia demonstrated significant antipsychotic efficacy (versus placebo). A 24-week, randomized, double-blind, active-controlled study in 1,065 schizophrenia patients stabilized with oral olanzapine demonstrated the depot formulation could delay exacerbation of positive symptoms or hospitalization. Apart from local injection reactions and a postinjection delirium/sedation syndrome, no new adverse events additional to those seen with oral olanzapine have been notedto date. The pivotal clinical trials of olanzapine rapid-acting intramuscular injection are reviewed in addition to post-hoc analyses, controlled and naturalistic studies since its launch.