Olanzapine long-acting injection: a review of its use in the treatment of schizophrenia

Olanzapine pamoate (olanzapine long-acting injection OLAI]; Zypadhera?; Zyprexa? Relprevv?) is the intramuscular depot formulation of the atypical antipsychotic olanzapine. In two pivotal, double-blind clinical trials of 8 or 24 weeks' duration, the efficacy of recommended dosages of OLAI injected every 2 or 4 weeks (without oral supplementation) was greater than that of placebo in improving symptoms in acutely ill patients with schizophrenia, and generally similar to that of continuing oral olanzapine in preventing psychotic exacerbations in patients with schizophrenia whose symptoms had previously been stabilized on oral olanzapine. The effectiveness of OLAI in the maintenance treatment of schizophrenia was also demonstrated in an (ongoing) open-label extension study in which the all-cause discontinuation rate was 34.3% after 18 months. OLAI is generally well tolerated. It has an adverse event profile similar to that of oral olanzapine, with the exception of adverse events related to the intramuscular route of administration; these include a manageable post-injection syndrome, which occurred in <0.1% of injections in clinical trials. The possibility of a post-injection syndrome event requires a risk management plan (RMP) to be adopted that includes observation by appropriately qualified personnel in a healthcare facility for at least 3 hours post-injection. With its potential to improve adherence to medication, and thereby treatment outcomes, OLAI is a useful addition to the pharmacological options available for the maintenance therapy of schizophrenia. Given its benefit/risk profile, OLAI appears most suited for patients who, despite responding well to oral olanzapine, have difficulties remaining adherent to this form of medication, provided they can comply with the conditions of the RMP.