Am Fam Physician. 2025;111(1):online
Author disclosure: No relevant financial relationships.
To the Editor:
Dr. Poorman and colleagues provided a comprehensive review of medications for alcohol use disorder (AUD).1 Although the authors included the current evidence supporting oral naltrexone and intramuscular naltrexone (Vivitrol), readers should be aware of the common concurrent use of alcohol and cocaine and the implications for AUD treatment. More than 70% of individuals who use cocaine are estimated to use alcohol concurrently, primarily for enhancing and prolonging the effects of cocaine.2,3 This practice is concerning, especially given the rise in stimulant-related drug overdoses over the past decade, which is driven by the increasing contamination of cocaine with fentanyl.4 In fact, a 2023 study showed that the rate of fentanyl contamination in powder cocaine was 14.8%.5
Although naltrexone is certainly one of the most effective medications for AUD, patients with fentanyl in their system can experience precipitated withdrawal upon taking naltrexone. Therefore, obtaining a comprehensive history of substance use and conducting regular urine drug screenings to detect unintentional opioid exposure because of contamination are encouraged before initiating naltrexone in individuals with AUD. This proactive approach will help ensure the safety and effectiveness of naltrexone treatment for AUD in the context of polysubstance use.
In Reply:
We thank Dr. Sonoda for noting this increasingly common clinical concern, especially given the rising level of fentanyl contamination in the cocaine drug supply. As we stated in our article, “naltrexone can precipitate severe opioid withdrawal, so opioids should not be used for at least seven days before starting naltrexone.”1 However, as Dr. Sonoda indicates, some clinicians may not be aware of the risk of unintentional fentanyl exposure. We similarly recommend that in practice, if patients are using any illicit substances in addition to alcohol (including cocaine, methamphetamines, and benzodiazepines), they be tested for fentanyl before the initiation of naltrexone and be advised on the risk of accidental overdose.
