Nalmefene HCl injection is now available for the complete or partial reversal of opioid drug effects including respiratory depression induced by natural or synthetic opioids, and in the management of known or suspected opioid overdose. Nalmefene HCl was approved by the FDA in February 2022. It was developed as an alternative to naloxone to reverse the effects of opioids, including respiratory depression, sedation, and hypotension. Nalmefene has been shown to have a longer duration of action than naloxone.
Nalmefene HCl can be administered via intravenous, intramuscular, or subcutaneous routes and is supplied as a single-dose vial containing 2 mg/2mL (1 mg/mL) of nalmefene base. It is a product of Purdue Pharma L.P., which is distributing it for no profit.
In pharmacokinetic study data, nalmefene HCl had an elimination half-life of 10.8 hours in males aged 19 to 32; in males aged 62 to 80, the elimination half-life was 9.4 hours.
Pulmonary edema, cardiovascular instability, hypotension, hypertension, ventricular tachycardia, and ventricular fibrillation have been reported in connection with opioid reversal. All drugs of this class should be used with caution in patients at high cardiovascular risk or who have received potentially cardiotoxic drugs. As with all opioid antagonists, there is a risk of precipitated withdrawal. Consult product labeling for full prescribing information.