Nalmefene and opioids: A contra-indication to remember

Abstract

Nalmefene (NMF – SELINCRO®), a drug for alcohol withdrawal management (AWM), is both a partial agonist and an antagonist of opioids receptors. Inherent to the latter activity, NMF is contra-indicated in patients with opioid treatment. However, despite this contra-indication, cases of opioid withdrawal syndrome (OWS) in patients treated with opioid maintenance therapy (OMT) are reported [1] , [2] . We aim to report 2 additional cases. A 46 and a 34-year-old men, with a history of alcoholism and opioid dependence, had OMT with methadone since a few years and were prescribed NMF. Thirty minutes after their single first dose of NMF, they experienced nausea, diarrhoea, vomiting and psychomotor excitement. First patient also had clonus, abundant sweating and anxiety. Both were transferred to the emergency department where OWS was diagnosed. They both received intravenous morphine, plus oxazepam (first patient) or a mix of benzodiazepines and neuroleptics (second patient). On the following day, first patient still presented digestive symptoms leading to hypokalaemia. A symptomatic treatment was initiated, morphine was stopped and methadone was reintroduced. He totally recovered on the 3 rd day and was discharged. The second patient was transferred into intensive care unit (ICU) as he required intubation and sedation. Two days later, morphine was stopped and methadone was reintroduced. The patient had totally recovered and was discharged two days later. Our two cases must be added to the nine other recently reported cases of OWS soon after a single first NMF intake in opioid dependent patients [1] , [2] . This condition always required hospitalization and sometimes ICU stay. No patient died. The summary of product characteristics of Selincro® has been updated in July 2015 with a clearer additional assertion to emphasize the need for healthcare professionals to be aware of their patients’ opioid consumption, especially OMT, before prescribing or delivering NMF. As co-existence of alcoholism and OMT is not rare, healthcare professionals really need to be vigilant about the contra-indication of NMF in patients under OMT.