One of the chief advocates for the controversial naltrexone implants, Perth-based Dr George O’Neil has defended the use of his experimental anti-heroin treatment, saying “the evidence is before our eyes”.

Using naltrexone implants to treat heroin addicts is controversial because the treatment has not yet been evaluated in rigorous clinical trials, and is not formally approved by health authorities. In yesterday’s Crikey, leading drug experts called for a halt to the wide scale use of the implants until there is better evidence for its safety and effectiveness.