Heroin prescriptions will be handed out to addicts in Canada for the first time. Getty

Prescription heroin will be given out to addicts for the first time in Canada this week.

Doctors won the right to prescribe heroin to 120 patients in their care after successfully overturning a federal government ban.

Under regulations introduced by health minister Rona Ambrose, heroin prescriptions could not previously be given to patients outside of medical trials.

But medics successfully requested an injunction against the ban at the Supreme Court in May.

Now doctors at the Providence Crosstown Clinic in Vancouver will be treating a total of 202 patients, of whom 120 have received diacetylmorphine (heroin) prescriptions. However, they will have to trial at least 11 alternatives, such as methadone, before prescribing heroin.

"The patients are so desperate for treatment, so desperate to be able to no longer be addicted," David Byres, vice-president of Acute Clinical Programs at Providence Health Care, told the Globe and Mail.

"It's a great thing to be able to help them, and help with the addiction that has taken over their entire lives."

The patients who are given the drug must attend the clinic at least three times a day to be monitored.

"This is safe, evidence-based treatment," said Dr Scott MacDonald, lead physician at Crosstown Clinic.

"When people first come off the street, they are often unstable. But within a few weeks here - and sometimes it's just days—we see a remarkable turnaround."

In the UK and other European countries including Germany and the Netherlands, prescription heroin is already been made legal.