Acute opioid withdrawal in the emergency department: inadvertent naltrexone abuse?

From July 1999 it became evident that a rising number of heroin users were presenting to the Dandenong Hospital Emergency Department with a rapid onset, florid opioid withdrawal syndrome following the intravenous injection of what they had believed to be heroin. We suspect that the injected substance was in fact naltrexone. This paper describes two such cases and reviews the literature on naltrexone. Recommendations regarding the management of the acute opioid withdrawal syndrome are made.