Compare Nalmefene to Naloxone for Opioid Overdose

This complimentary article from Hospital Pharmacist’s Letter is being provided to readers of Prescriber’s Letter, who may find its content relevant to their practice.



Nalmefene is a new option to reverse opioid overdose in the emergency department.

The manufacturer is relaunching nalmefene at “no profit” part of the settlement in OxyContin lawsuits.

But nalmefene is not costs within the ballpark of naloxone.

Both meds work similarly...but the kinetics are different.

Nalmefene has a slower onset than naloxone...about 5 minutes versus 2 minutes. And nalmefene lasts longer...up to about 4 hours versus 2 hours.

Its longer duration is why you’ll hear that nalmefene is a better choice for long-acting opioid overdoses.

But there’s no good evidence that nalmefene is more effective.

Plus nalmefene’s longer duration might prolong withdrawal.

Continue to rely on naloxone as your workhorse.

Watch for mix-ups if your hospital adds nalmefene to formulary...or uses it due to a naloxone shortage.

For instance, nalmefene is IV, IM, or subcutaneous. Naloxone can be given by additional routes...intranasal, endotracheal, etc.

And for now, nalmefene is only for administration by healthcare staff. Continue to provide a discharge Rx for naloxone for patients at risk of opioid overdose.

Use our resource, Meds for Opioid Overdose, to compare dosing, find tips about providing naloxone at discharge, and more.

Key References

  • Ann Emerg Med. 1999 Jul;34(1):42-50
  • Pharmacol Ther. 2022 May;233:108019
  • Psychiatry Int. 2021;2(4):365-378
  • J Med Toxicol. 2020 Jan;16(1):41-48
  • Medication pricing by Elsevier, accessed Jul 2022
Prescriber's Letter. August 2022 No. 380818

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