FDA Approves Nalmefene Nasal Spray for Opioid Overdose

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The approval was based on data from a pharmacodynamic study which showed nalmefene provided a fast onset of reversal of respiratory depression from the synthetic opioid remifentanil.

The US Food and Drug Administration (FDA) has approved nalmefene (OPVEE) nasal spray for the emergency treatment of opioid overdose, either known or suspected, caused by natural or synthetic opioids, including fentanyl, in adults and pediatric (aged ≥12 years) patients. The approval was based on data from a first of its kind pharmacodynamic study which showed that the drug provided a fast onset of reversal of respiratory depression from the synthetic opioid remifentanil.

Nalmefene is an opioid receptor antagonist that provides both fast onset and long duration reversal of opioid-induced respiratory depression. It was designed to tackle to challenges of the current opioid crisis.

“In the 12-month period ending in December 2022, over 79,000 people in the US were reported to have died of an opioid overdose, of which 90% – approximately 72,000 – were linked to illicit synthetic opioids, mainly fentanyl,” the press release stated.1

The pharmacodynamic study evaluated the effect of 2.7 mg nalmefene on remifentanil-induced respiratory depression in 61 opioid-experienced, non-dependent participants. After initiating the drug, the time to onset of reversal of respiratory depression was 2.5 to 5 minutes, and full recovery was demonstrated as early as 5 minutes. Nalmefene was also shown to have a terminal plasma half-life of approximately 11 hours.

The most common adverse reactions included headache, nausea, nasal discomfort, nasal congestion, fatigue, anxiety, hot flush, erythema, decreased appetite, and vomiting.

"Despite our collective effort to stem opioid abuse in America, addiction can happen to anyone, and millions of people are at risk for not only opioid overdose, but also poisoning from illicit synthetic opioids such as fentanyl," stated Jerome Adams, MD, MPH, executive director of Health Equity Initiatives, Purdue University. "With OPVEE, first responders will have a fast and long-acting rescue medication option to combat the current opioid epidemic and save lives."1


  1. Cision. (2023, May 22). Indivior announces U.S. Food and Drug Administration approval of OPVEE® (NALMEFENE) nasal spray, an opioid overdose rescue medicine for natural and synthetic opioids like fentanyl. PR Newswire: press release distribution, targeting, monitoring and marketing.