STAMFORD, Conn., March 27, 2024 – Purdue Pharma L.P. (“Purdue”) announced today that the Company has awarded an investigator-initiated research (IIR) grant to a team of researchers at The University of New Mexico (UNM) for the evaluation of nalmefene hydrochloride (HCl) injection 2mg/2mL (1mg/1mL) in the emergency department setting.

Opioid overdoses are sadly way too common in New Mexico,” said Cameron Crandall, MD, with UNM’s School of Medicine, Department of Emergency Medicine. “Having this treatment available can help save lives. Nalmefene helps reverse the deadly effects of opioid overdoses and is long-acting. We are evaluating its effects on patients who present in the ED with opioid overdose.”

Investigator-initiated research projects like this can help provide a better understanding of nalmefene HCl injection’s use in real-world emergency department settings,” said Monica Kwarcinski, PharmD, Vice President, Medical Affairs at Purdue. “We are enthusiastic about supporting research that can contribute to addressing the opioid overdose crisis.”

The prospective, randomized study, “Evaluation of Nalmefene HCl Injection for Recurrent Respiratory Depression After Suspected Acute Opioid Overdose in an Emergency Department,” will compare the efficacy and safety of nalmefene HCl injection to naloxone injection in the treatment of recurrent respiratory depression due to opioid overdose. The objective is to evaluate these treatments in reversing symptoms of opioid overdose. The study will also assess adverse events, including the development of precipitated opioid withdrawal, following the administration of each treatment.

Nalmefene HCl injection is 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. Nalmefene Hydrochloride injection is contraindicated in patients with a known hypersensitivity to the product.1 The Company distributes nalmefene HCl injection for no profit.

The study will be independently developed and carried out by UNM’s research team with Purdue Pharma providing only funding and nalmefene HCl injection. Patient enrollment is planned to begin in July 2024.



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

Please read Prescribing Information available here.

For more information, visit

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 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.

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About The University of New Mexico Research

As an R1 university, The University of New Mexico serves as the state’s premier institution of higher learning and provider of health care by promoting discovery, generating intellectual and cultural contributions, and honoring academic values.

As the only academic health center in New Mexico, UNM Health and Health Sciences is dedicated to pushing forward into uncharted research territory. Faculty, staff, and trainees work tirelessly to address New Mexico’s pressing health needs. At any given time, UNM Health and Health Sciences manages over 300 clinical trials and 900 major research projects. UNM’s influence continues to grow through innovative medical research that reaches every corner of the globe.


  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/​s​p​l​/​d​a​t​a​/​d​4​b​b​0​7​9​7​-​a​4​e​d​-​4​e​d​4​-​9​9​0​4​-​6​0​4​4​3​3​e​e​a​4​f​f​/​d​4​b​b​0​7​9​7​-​a​4​e​d​-​4​e​d​4​-​9​9​0​4​-​6​0​4​4​3​3​e​e​a​4​f​f.xml Accessed Feb. 8, 2024

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