A review of olanzapine pamoate

Introduction: Olanzapine long-acting injection (OLAI), or olanzapine pamoate, is one of three second generation (SGA) antipsychotics now available in a long-acting formulation. OLAI is a microcrystalline salt of pamoic acid and olanzapine suspended in an aqueous solution that slowly dissociates into the separate components once injected intramuscularly (im) into gluteal muscle. Areas covered: A systematic search of databases including PubMed, PsychInfo, and Embase was conducted using the keywords. Relevant articles were then hand searched and relevant websites (FDA, EMA, Eli Lilly, and NIH) were also reviewed. Expert opinion: Efficacy has been demonstrated in the short term and maintenance treatment of schizophrenia with OLAI at doses of 150 – 300 mg every two weeks or 405 mg every four weeks. The overall side effect profile is similar to oral olanzapine. While injection site complications are mild, there is an incidence rate per injection of 0.07 % (incidence rate per patient of 1.4%) of post-injection delirium sedation syndrome (PDSS). This manifests as overdose-like symptoms which necessitates mandatory administration and continuous monitoring of OLAI by health care professionals for the first three hours in a suitable clinical facility. As a consequence, final regulatory approval was delayed and market release and clinical use have been limited.