Naltrexone for problem gamblers

By Dr. Ananya Mandal, MDNov 22 2011

According to new practice guidelines Australian doctors treating gambling addicts now can consider prescribing an anti-heroin drug, naltrexone, to help problem gamblers control their impulses. Australia has one of the world’s highest rates of problem gamblers, with about 2.1 per cent of Australians experiencing some form of gambling problem.

The guidelines came from the Medical Journal of Australia’s website. It calls on practitioners to treat gambling addiction as a medical problem and recommends the use “with caution” of the drug naltrexone. The drug, usually used to treat problems such as heroin and alcohol addictions, can help to block the overproduction in the brain of endogenous opioids and to assist people to control their impulses.

The director of Australia’s Problem Gambling Research and Treatment Centre, Shane Thomas, said psychological programs were preferable to naltrexone, but a small number of case studies had shown the drug could be a useful treatment tool. “I think the current evidence is in favor of psychological therapies,” he told ABC Radio.

“People are often very interested in the use of pharmacological agents for treatment of conditions because they hope it will be sort of the golden bullet, that we can take a pill and cure or attend to these problems.” Professor Thomas said naltrexone had side-effects such as abdominal pains and further research was still needed to determine its effectiveness as an anti-gambling treatment.

“There are some promising indications,” he said. “So our recommendation is that this is definitely the subject of further research to determine the effectiveness.”

Interest has also switched to naltrexone implants, and more recently long-acting injectable forms that are claimed to work for 30 days, which proponents say reduces the risk of a fatal overdose because these formulations do not rely on addicts taking a daily naltrexone tablet.

The National Health and Medical Research Council, this year issued a position statement that found the research was “at an early stage” and naltrexone implants “remain an experimental product and should only be used in a research setting”. “Until the relevant data are available and validated, the efficacy of the (naltrexone implant) treatment, alone or in comparison to best practice, cannot be determined,” the statement said.

Gary Hulse, professor of addiction medicine at the University of Western Australia, was lead author of a 2009 study that found implants reduced relapse to heroin use compared with oral naltrexone, and were not linked to major adverse events. “It's time there was renewed interest in it,” Professor Hulse said. “Australia at one time was leading the world in terms of this technology.”

However Alex Wodak, director of the alcohol and drug service at Sydney's St Vincent's Hospital, said much of the research supporting naltrexone was flawed, and implants were strongly supported by some for ideological grounds - that complete abstinence from illicit drug use was the only acceptable goal. Naltrexone “has very low support from most people who highly value science, human rights and ethics”, Dr Wodak said.

The guidelines have been approved by the head of the federal government’s main health and clinical advice body, the National Health and Medical Research Council. The guidelines also recommend a range of psychological interventions but advise that antidepressant medications should not be used to reduce gambling severity in people with gambling problems alone.