When it comes to treatment of heroin dependence, the drug buprenorphine, which is marketed as Temgesic or Buprenex, is twice as effective as a rival treatment called naltrexone, a new study has found.

The study, led by Yale University's Richard Schottenfeld, was carried out on 126 patients in Malaysia for 22 months. All subjects, who had recently undergone a detoxification and counselling programme, were tested with two drugs.

In terms of days of abstinence from heroin and a complete relapse to the narcotic, researchers found that buprenorphine was twice as effective as naltrexone (branded as Revia, Depade or Vivitrol) and the placebo. Results of the study were published Friday in the Lancet.

The three drugs belong to a class called opioid antagonists and are used in heroin de-addiction but remain prohibited in some countries for fear that they can be abused or simply substitute one addiction for another.

The study suggested that buprenorphine should be placed alongside methadone as pharmacological treatments for helping addicts stay off heroin. It did not favor naltrexone usage in treatment.