Questions are being raised about how the strictly controlled drug methadone is dispensed in Nova Scotia after a 20-year-old Greenwood woman died last week of an overdose.

Police in the Annapolis Valley are continuing their investigation into the final hours of Katanna MacDonald's life.

MacDonald was taking methadone to treat her drug addiction but it's not clear whether she got her methadone from the Annapolis Health Authority clinic or if she bought it on the street.

Methadone is used to treat opiate addicts and works by blocking opioid receptors in the brain to take away cravings and prevent withdrawal symptoms. It is taken orally, usually mixed with juice.

In most cases, the methadone must be taken in front of a witness, but some patients are allowed 'carries', that is they're allowed to carry the methadone away from where it's distributed.

Dr. John Campbell, director of addiction services at the Annapolis Valley Health Authority, said they do not know whether they were the source of the methadone in the fatal overdose.

"We seriously don't know," Campbell said. "We don't know the circumstances surrounding it. We think it is a tragedy and we will fully co-operate with any investigation surrounding this death."

The hospital said it has yet to hear from the RCMP, which said its still waiting for toxicology reports to confirm methadone caused the death.

But MacDonald's father, Jim, has no doubt about how his daughter died.

"It was methadone, that's what the doctors told us right from the start, that's what it was," he said.

He said that doctors told him tests at the time of MacDonald's death showed she had methadone in her blood stream.

Staff Sgt. Jean Guy Richard, of the Kings District RCMP, said their investigation continues.

"Our investigators are interviewing anyone that would have been in contact with Ms. MacDonald prior to her death just basically to establish a time line."

Police are also investigating another sudden death in the Kingston-Greenwood area. June Christian, a chronic alcoholic and hydromorphone addict, died earlier this month.

Benefits outweigh risks, doctors say

Regardless of the risks, doctors who prescribe methadone say it's almost a miracle cure for opiate addiction and allowing addicts to take a small supply home is valuable incentive to stay clean.

Dr. Don Fay told CBC News that methadone is an important tool in addiction treatment.

"It's a tremendous reward system too, if you have done your work properly," Fay said. "You've stayed on the program, you've stayed off other drugs, adhered to the program, let's say Direction 180, and you've shown that you can do that well then you earn carries."

Methadone relieves the pain and sickness that comes from drug withdrawal.

Currently, 1400 people in Nova Scotia have a legal prescription to use it.

Of those, 1200 are 'carries' users, that are allowed to take a supply of methadone home.

Janet Webster has been taking methadone for the past four years to help fight her addiction to Dilaudid.

She said the drug is saving her life, but she said the methadone found on the streets can be lethal.

"Who knows what people are getting when they buy it [off the streets]. Basically they're taking a loaded gun, pointing it at their head and they're hoping it's not loaded," Webster said. "The fact is they could very easily die from it."

Many people with a carry away prescription for methadone pick it up at a clinic in the north end of Halifax.  

Before they're given their first prescription, the pharmacist will check to make sure they're not agitated or intoxicated and that first dosage is consumed onsite to make sure the methadone is indeed going to the patient.

After that regular urine samples are taken to monitor usage.

People like Janet Webster who are regular users of methadone say regardless of the controls at pharmacies methadone does make it to the streets.

While that's a risk, doctors say the biggest problem with methadone isn't it's presence on the street, but rather getting it to the growing number of people in the province who need it.

Methadone treatment facility in favour of more strict controls

Cindy MacIssac, executive director of Direction 180, said she is in favour of tighter controls of the drug.

Direction 180 is a community-based methadone clinic located in the north end of Halifax and has been running since 2001.

In the Halifax area alone, there are 300 people waiting to access methadone treatment. Staff at Direction 180 are currently treating 230 people. The long waiting list for treatment is due to lack of resources, said MacIssac.

"We need to ensure that those that are getting methadone and have carries are following the treatment guidelines and we also need to ensure that the demand for diverted methadone is reduced," she said.

MacIssac said there are several ways to ensure methadone doses reach the people they are intended for: by ensuring people are ingesting their methadone twice weekly in front of a pharmacist, ensuring they return their bottles, random urine analysis and closer observation for those who do relapse.

"I think provincially, we need to look at safeguarded seals so the pharmacies, at random, can call the methadone bottles back to ensure they haven't been tampered with," she said.

MacIssac said she's concerned there could be a backlash against methadone.

"My heart goes out to the family of the young lady who overdosed as a result of the diverted methadone but I think we need to look at this more broadly and I think the province has to step up and we need to ensure that people have more timely access to treatment," she told CBC News.