Results of US review into the deaths of two patients taking Eli Lilly’s long-acting antipsychotic Zyprexa Relprevv (olanzapine pamoate) are inconclusive.

The US Food and Drug Administration launched an investigation in June last year into the cause of high levels of the drug found in two patients who died three to four days after taking it.

“We are unable to exclude the possibility that the deaths were caused by rapid, but delayed, entry of the drug into the bloodstream following intramuscular injection,” the regulator said. However, on the basis of all of the information reviewed, it is not recommending any changes to current prescribing or use.

Zyprexa Relprevv’s label already carries a boxed warning for post-injection delirium sedation (PDSS), a serious condition with signs and symptoms consistent with olanzapine overdose, after it was observed in clinical trials within three hours after administration. 

To cut the risk of PDSS, a Risk Evaluation and Mitigation Strategy is in place to ensure that patients are observed by healthcare professionals at a certified facility following injection.