A controversial surgical implant is being used to treat addiction to meth, or ice, in Australia, which is the second most commonly used drug next to marijuana.

More than 300 people with drug problems each year consent to receive a naltrexone implant from the Fresh Start clinic in the city of Perth run by Dr. George O'Neil, one of the few Victorian doctors who is willing to install the devices.

Naltrexone is an opioid antagonist which has been demonstrated to reduce the reward associated with drug-taking. “With amphetamine addicts, it just isn't as enjoyable as it used to be,” on naltrexone. “And so the reward is reduced,” Dr. O'Neil said.

But naltrexone treatments often run into problems with attrition and compliance, where drug users intentionally skip doses in order to get high or stop taking the buzz killing treatment altogether. The implant, which is surgically placed in the patient's abdomen, removes the problem of compliance by slowly releasing naltrexone into the bloodstream maintaining an effective dose at all times, irrespective of the users wants on a given day.

Nicole Leek, an associate professor who researches drug addiction, told ABC that “Naltrexone's been trialed three or four times for ice addicts and it's not really been shown to be particularly effective.”

Dr. O’Neil, who runs a naltrexone clinic, disagrees, arguing it is one of the more effective treatments. He says the implant has a bad reputation because other clinics provide inferior devices which dispense incorrect doses.

In 2012, a coroner found three patients addicted to heroin passed away after getting naltrexone implants at a Sydney clinic. The danger of the implant, and naltrexone in general, is after it is used for a lengthy period of time, a user's tolerance for opiates will be significantly reduced.

Once the antagonist wears off and a user returns to using opiates with a dramatically reduced to tolerance, the risk of overdose becomes much higher.