Unplanned admissions to two Sydney public hospitals after naltrexone implants

To the Editor: We read with interest the report of 12 hospital presentations related to the use of naltrexone implants.1 The accompanying editorial highlights how the rigorous scrutiny required to evaluate the efficacy and safety of this procedure is lacking.2 Regrettably, this study is likely to distort rather than inform the debate.

Lintzeris and colleagues1 only identified patients with naltrexone implants who were referred to the Drug and Alcohol Consultation–Liaison services, not all patients presenting to the study hospitals. Additionally, the authors did not follow the methodology of chart reviews, as recommended by Gilbert and colleagues.3 Four of the 12 patients clearly had problems unrelated to their naltrexone implants. There was no attempt to identify the number of naltrexone implantations performed (ie, the denominator), nor was there any attempt to compare the naltrexone group with others being treated with agents such as methadone or buprenorphine.

In 2003, we published our experience of naltrexone-accelerated detoxification in the emergency department (ED) of Sir Charles Gairdner Hospital.4 The hospital’s clinical toxicology service is based in the ED, and the hospital is located 2 km from the only private clinic in Perth that was using naltrexone during the study period in 2001. Working collaboratively with this clinic, patients developing complications from detoxification were referred to our service. In 6 months, 42 patients (7% of all those receiving naltrexone treatment) presented to the ED — 17 within 24 hours of treatment and 31 within 48 hours. Gastrointestinal symptoms of withdrawal were present in 18 patients, and central nervous system symptoms of withdrawal (predominantly agitation) in 14. Two patients required intubation for airway compromise secondary to a combination of agitation and chemical sedation. In 23 patients receiving naltrexone implants (rather than oral therapy), three developed infections and three complained of local pain. The mean length of stay for all patients was 18 hours (compared with 2.3 days in Lintzeris et al’s study), with the longest stay being 92 hours for one of the patients admitted to the intensive care unit. During the study period and the subsequent 6 months, four deaths of individuals who had undergone naltrexone-accelerated detoxification were reported to the Coroner, all being classified as probable drug overdose, probably opioid. None of these patients had presented to the hospital’s ED during the study period.

It is important that good data are made available to inform the debate on naltrexone implants in the management of opioid dependence. Better communication and collaboration between clinics using naltrexone, EDs, and alcohol and drug services will improve the care of these patients.