FDA Approves First Nalmefene Auto-Injector for Opioid Overdose

The US Food and Drug Administration (FDA) has approved the first nalmefene hydrochloride auto-injector (Zurnai; Purdue Pharma LP) for the treatment of known or suspected opioid overdose in people aged 12 years or older.

Zurnai delivers 1.5 mg of the opioid receptor antagonist nalmefene subcutaneously or intramuscularly and is a single-dose, prefilled auto-injector that is available by prescription only. If administered quickly, it can reverse respiratory depression, sedation, hypotension, and other symptoms of opioid overdose.

“The FDA remains focused on broadening access to opioid overdose reversal agents, including naloxone and nalmefene. Today’s approval adds a new nalmefene product and route of administration to support greater options for opioid overdose reversal,” FDA Commissioner Robert M. Califf, MD, said in a statement.

The statement cited “safety and pharmacokinetic studies” in its approval of Zurnai, along with a study in healthy recreational opioid users to assess how quickly the product works.

Common adverse reactions include feeling hot, dizziness, nausea, headache, chills, vomiting, allodynia, palpitations, tinnitus, ear discomfort, feeling abnormal, burning sensation, hot flush, and irritability.

The treatment is contraindicated in patients known to be hypersensitive to nalmefene hydrochloride or to any other ingredients in the product. Reversal of respiratory depression by partial agonists or mixed agonists/antagonists, such as buprenorphine and pentazocine, may be incomplete. Repeat doses of Zurnai may be required.

“We are pleased to gain approval of Zurnai, the nalmefene auto-injector, for use by healthcare professionals or anyone in the community,” Craig Landau, MD, president and CEO of Purdue, Stamford, Connecticut, said in a statement. “Zurnai can be an important new tool to save lives in critical moments. We are committed to delivering solutions to help address the opioid overdose crisis and are working to provide Zurnai at no profit to the Company.”

The new drug application was granted Fast Track and Priority Review designations. Nalmefene injection was originally approved by the FDA in 1995. The agency approved the first nasal spray formulation of nalmefene in May 2023.

Kelli Whitlock Burton is an assistant managing editor for Medscape who covers neurology