Nalmefene Hydrochloride Injection is now available for the complete or partial reversal of opioid drug effects, including respiratory depression, induced by either natural or synthetic opioids, and in the management of known or suspected opioid overdose.

The Food and Drug Administration (FDA) approved Nalmefene in February 2022 and was developed as an alternative to naloxone to reverse the effects of opioids, including respiratory depression, sedation, and hypotension. The drug was previously marketed under the brand name Revex (Baxter) but was discontinued in 2008.

Pharmacodynamic studies have shown that nalmefene has a longer duration of action than naloxone. Nalmefene HCl can be administered via the intravenous, intramuscular, or subcutaneous route.

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The most common adverse reactions reported in clinical trials with nalmefene injection were nausea (18%), vomiting (9%), tachycardia (5%), hypertension (5%), postoperative pain (4%), fever (3%), and dizziness (3%). 

Nalmefene Hydrochloride Injection is supplied as a single-dose vial containing 2mg/2mL (1mg/mL) of nalmefene base in a carton of 10 vials.

“We believe nalmefene will be an important treatment option to help address the growing and continuing crisis of opioid overdose deaths, including those due to fentanyl and other synthetic opioids,” said Craig Landau, MD, President and CEO, Purdue Pharma. “[…] we are distributing this medication for no profit, as part of our commitment to contribute meaningful medicines to help abate the opioid crisis.”


  1. Purdue Pharma introduces Nalmefene HCl Injection, 2mg/2mL (1mg/1mL) in the US for the treatment of known or suspected overdose with natural or synthetic opioids. News release. Purdue Pharma L.P. Accessed June 21, 2022.
  2. Nalmefene Hydrochloride Injection. Package insert. Purdue Pharmaceuticals, LP; 2022. Accessed February 23, 2022.

This article originally appeared on MPR