Nalmefene Mistakenly Prescribed to Reduce Alcohol Consumption in Patients Under Buprenorphine Substitution Therapy Resulting in Acute Opioid Withdrawal: Management in an Emergency Setting

Opioid Withdrawal Precipitated by Long-Acting Antagonists

BACKGROUND

Precipitated opioid withdrawal (POW) after opioid antagonist administration can be challenging to manage in the emergency department (ED), particularly if caused by a long-acting opioid antagonist such as naltrexone. There are no evidence-based guidelines to assist in safely and efficiently managing patients with this syndrome.

OBJECTIVE OF REVIEW

To review current practice on the treatment of long-acting antagonist POW and make recommendations on the treatment of this complex disease process.

METHODS

A literature search of opioid withdrawal cases precipitated by naltrexone was done using PubMed. One of the authors screened all the results of this search by title and abstract, leading to a final count of 27 articles that were reviewed in full by all authors. English language cases that involved precipitated opioid withdrawal from a long-acting opioid antagonist were included. Data were extracted, including the precipitant involved and dose, severity of opioid withdrawal, treatments rendered, and response to treatment. In all cases where symptoms and signs were described, a Clinical Opiate Withdrawal Scale score was calculated based on the information available.

RESULTS

Twenty-seven papers were included. Naltrexone alone was the primary antagonist reported in 19 of the papers, extended-release naltrexone in two, naltrexone-morphine combination in two, and nalmefene in four. Treatment most commonly included fluid replacement, benzodiazepines, antiemetics, and clonidine. Full opioid agonist treatment, although often suggested, was poorly described. Buprenorphine successfully reduced the severity and duration of withdrawal in several cases. No standardized response scale was used, and response to treatment ranged from 3 to 48 h prior to resolution of clinical effects.

CONCLUSIONS

Management of POW from long-acting antagonists is a complex problem with little formal evaluation of treatment options. There is not currently a sufficiently robust body of literature to support an evidence-based guideline. However, use of intravenous fluids, antiemetics, and benzodiazepines is commonly reported as successful and seems to be a reasonable approach until this process is better studied. A treatment strategy using partial agonists such as buprenorphine is emerging and may represent a safe and effective treatment pathway for these patients.