FDA Accepts Filing of New Drug Application for Nalmefene Auto-injector for the Treatment of Known or Suspected Opioid Overdose


STAMFORD, Conn.--(BUSINESS WIRE)-- Purdue Pharmaceuticals, L.P.. (“Purdue”) announced today that FDA has accepted for filing the company’s New Drug Application (NDA) for the auto-injector delivery form of nalmefene hydrochloride injection*. If the auto-injector is approved, it would be the second nalmefene-containing medicine developed by Purdue to specifically address the growing number of opioid overdose deaths, including those due to fentanyl and other synthetic opioids. It would be the first nalmefene medicine available as an auto-injector.

Purdue developed the nalmefene auto-injector because it is a type of device familiar to the U.S. population through experience with similar devices on the market used for severe allergic reactions. If approved, the nalmefene auto-injector could be used by healthcare professionals and first responders, as well as laypersons without medical training such as bystanders, caregivers, or family members.

“As part of our Public Health Initiatives, we are committed to providing essential opioid overdose treatments to help save lives in our communities,” said Craig Landau, MD, President and CEO, Purdue. "Through this auto-injector FDA submission, our goal is to help expand the availability of nalmefene to the community alongside existing available options for healthcare professionals. If approved, we would distribute this medication for no profit, as part of our commitment to help abate the opioid crisis.”

FDA has granted a priority review for the NDA and assigned a goal date of August 7, 2024. Priority review status means that FDA will expedite the review process to evaluate a drug that would significantly improve treatment of a serious condition.

Purdue currently distributes, at no profit, nalmefene hydrochloride injection, 2mg/2mL (1mg/1mL), an opioid antagonist indicated 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.1 Healthcare professionals can learn more about injectable nalmefene at www.nalmefenehcl.com.

*This release discusses investigational uses of agents in development and is not intended to convey conclusions about efficacy or safety. There is no guarantee that nalmefene autoinjector will successfully complete development or gain FDA approval.



Nalmefene Hydrochloride Injection is indicated for the complete or partial reversal of opioid drug effects, including respiratory depression, induced by either natural or synthetic opioids.

Nalmefene Hydrochloride Injection is indicated in the management of known or suspected opioid overdose.


Nalmefene Hydrochloride injection is contraindicated in patients with a known hypersensitivity to the product.


Use of Nalmefene Hydrochloride injection in Emergencies

Nalmefene Hydrochloride injection, like all drugs in this class, is not the primary treatment for ventilatory failure. In most emergency settings, treatment with Nalmefene Hydrochloride injection should follow, not precede, the establishment of a patent airway, ventilatory assistance, administration of oxygen, and establishment of circulatory access.

Risk of Recurrent Respiratory Depression

Accidental overdose with long acting opioids [such as methadone and levo-alpha-acetylmethadol (LAAM)] may result in prolonged respiratory depression. Respiratory depression in both the postoperative and overdose setting may be complex and involve the effects of anesthetic agents, neuromuscular blockers, and other drugs. While Nalmefene Hydrochloride injection has a longer duration of action than naloxone in fully reversing doses, the physician should be aware that a recurrence of respiratory depression is possible, even after an apparently adequate initial response to Nalmefene Hydrochloride injection treatment.

Patients treated with Nalmefene Hydrochloride injection should be observed until, in the opinion of the physician, there is no reasonable risk of recurrent respiratory depression.

Cardiovascular Risks with Narcotic Antagonists

Pulmonary edema, cardiovascular instability, hypotension, hypertension, ventricular tachycardia, and ventricular fibrillation have been reported in connection with opioid reversal in both postoperative and emergency department settings. In many cases, these effects appear to be the result of abrupt reversal of opioid effects.

Although Nalmefene Hydrochloride injection has been used safely in patients with pre-existing cardiac disease, all drugs of this class should be used with caution in patients at high cardiovascular risk or who have received potentially cardiotoxic drugs.

Risk of Precipitated Withdrawal

Nalmefene Hydrochloride injection, like other opioid antagonists, is known to produce acute withdrawal symptoms and, therefore, should be used with extreme caution in patients with known physical dependence on opioids or following surgery involving high doses of opioids. Imprudent use or excessive doses of opioid antagonists in the postoperative setting has been associated with hypertension, tachycardia, and excessive mortality in patients at high risk for cardiovascular complications.

Incomplete Reversal of Buprenorphine

Preclinical studies have shown that nalmefene at doses up to 10 mg/kg (437 times the maximum recommended human dose) produced incomplete reversal of buprenorphine-induced analgesia in animal models. This appears to be a consequence of a high affinity and slow displacement of buprenorphine from the opioid receptors. Hence, Nalmefene Hydrochloride injection may not completely reverse buprenorphine-induced respiratory depression.

Use in Pediatric Patients

Safety and effectiveness of nalmefene hydrochloride injection in pediatric patients have not been established.


The most common adverse reactions (>1%) reported in clinical trials with nalmefene injection were nausea (18%), vomiting (9%), tachycardia (5%), hypertension (5%), postoperative pain (4%), fever (3%), and dizziness (3%).

To report SUSPECTED ADVERSE REACTIONS, contact Purdue Pharma L.P. at 1-888-726-7535 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch.

Please read Prescribing Information available here.

For more information, visit www.nalmefenehcl.com.

About Purdue Pharma L.P.

Purdue Pharma and its subsidiaries develop, manufacture and market medications to meet the evolving needs of healthcare professionals, patients, and caregivers. Purdue’s plan of reorganization will deliver billions in value to communities across the country to fund programs specifically for abatement of the opioid crisis. The bankruptcy settlement will also deliver funds to private abatement trusts for the benefit of personal injury claimants.

Substantially all of Purdue’s assets will be transferred to a new post-emergence company with a public-minded mission. This new company will be governed by new independent board members and will operate in a responsible and sustainable manner taking into account long-term public health interests relating to the opioid crisis. The company will continue serving patients who rely on its medicines, pursuing its pipeline and introducing medicines that will help save and improve lives.

For more information, visit www.purduepharma.com.


  1. Nalmefene Hydrochloride Injection 2mg/2mL (1mg/1mL) [Full Prescribing Information]. Stamford, CT: Purdue Pharma L.P., 02/08/2022. https://www.accessdata.fda.gov/spl/data/d4bb0797-a4ed-4ed4-9904-604433eea4ff/d4bb0797-a4ed-4ed4-9904-604433eea4ff.xml. Accessed February 14, 2024.



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Source: Purdue Pharma L.P.

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