Leading Australian figures with expertise on illicit drugs want to shut down the routine prescribing of naltrexone implants, a controversial treatment for heroin addiction pushed zealously by a small group of devout doctors based in Perth and Brisbane, with support from the Federal Government.

Given the sensitivities of drug policy, and widespread fear of criticising Canberra, the call to shut down the controversial treatment is particularly significant.

Unlike the more established treatments, including methadone, the drug naltrexone works to strongly negate the impacts of heroin. As a consequence, one of the problems is that after completing a course of naltrexone, a drug user’s tolerance for heroin is so diminished that a usual-sized dose can prove fatal.

Naltrexone implants have not yet been rigorously evaluated in clinical trials, nor gained formal approval from the Therapeutic Goods Administration, yet a Perth doctor has implanted 2000 into heroin addicts in his Perth clinic. With the blessing of the Federal Government, the clinic uses a special exemption to the drug regulations allowing the prescription of new and experimental treatments.

University of Queensland Public Health Professor Wayne Hall says the routine prescribing of unproven naltrexone implants is a “circumvention of standard protections”. He says the program should be shut down and implants used only in the context of properly conducted clinical trials. A small trial is currently underway, but its results are not yet published.

The call to stop the experimental treatment is backed by the director of the prestigious National Drug and Alcohol Research Centre, Professor Richard Mattick. “It is not appropriate to have wide-scale prescribing of something that hasn’t gone through normal regulatory processes,” he told Crikey. “There are significant dangers in promoting this.”

One of the first scientific evaluations of the deaths associated with the drug was published by the NDARC two years ago. It showed that in the early 2000s, oral naltrexone, which was used in tablet form before the advent of the implant, was four times more likely to be associated with death as methadone. A more recent piece published in the Medical Journal of Australia in early 2007 highlighted several cases of deaths associated with the implant.

Internationally known expert on treating illicit drug users, Dr Alex Wodak, also backs the call to use the unproven implant only in the context of a trial. “It’s unsafe until proven otherwise” he says. All three critics believe there is a place for naltrexone in treating certain addicts, but only after much more rigorous scientific trials.

The head of the naltrexone clinic in Perth, Dr George O’Neil, argues the implants are safe. But he concedes that in an ideal world, good trials would have been done before widespread use.

Tomorrow, praise for naltrexone from the devout.

Peter Fray

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Peter Fray
Editor-in-chief of Crikey