HALIFAX -- More than 2,100 Nova Scotians have been given big-dose prescriptions of highly addictive painkillers this year, and addictions experts say the "disturbing" number demands the province must reform doctors' prescribing habits.

Figures provided to The Canadian Press indicate 2,113 patients are receiving levels of opioids of 200 milligrams or more per day of morphine -- enough to cause a fatal overdose to a newcomer to opioids.

Dr. Gus Grant, the registrar of the province's College of Physicians and Surgeons, said the college is continuing to monitor physicians' prescribing habits, and has been stepping up efforts to educate physicians to shift away from large prescriptions.

"To me it's a disturbing number. It indicates we have a large cohort of patients maintained on dosages of medicine that are really unsupported by evidence and which exposes these patients to risks that exceed the benefits," he said in a telephone interview on Monday.

"It demonstrates the problem is of a scale that few outside the medical profession can really appreciate."

He said it's important to recall that about one fifth of the patients are being treated for cancer and may need larger prescriptions for end-of-life care, and said he's encouraged the prescription monitoring program's figures show a decrease from the 2,507 patients on opioids in 2015.

The prescription figures come just weeks after the province announced a task force to consider ways to avoid a British Columbia-style overdose epidemic, while informing the public there have been 49-opioid-related deaths caused both by street drugs and prescriptions.

The Canadian guidelines were created in 2010 by the national pain centre at McMaster University. They say chronic non-cancer pain can be managed effectively "in most patients" with the dosages of 200 milligrams per day of morphine or the equivalent, and says anything higher requires "careful re-assessment."

The Nova Scotia college has gone further, adopting as "best practice" a guideline from the U.S.-based Centers for Disease Control and Prevention to avoid doses in excess of 90 milligrams.

Grant said if physicians are consistently departing from this practice, "they should be prepared to justify the departure."

Every six months, the 100 physicians with the highest risk profiles are contacted and given a detailed description of their prescribing habits. They are also given resources to "help them engage in reflection on their prescribing," he said.

"Physicians should be aware of the best evidence and be able to answer as to why their practice might not be in alignment," he wrote in an email.

On the other hand, he said it is going to take time to gradually shift patients off big dosages.

"You simply can't abandon these patients who are in a situation of being maintained on these large doses. It has to be done over a long period of time," he said.

Benedikt Fischer, a senior scientist at the Centre for Addiction and Mental Health in Toronto, said the dosages being documented by the Nova Scotia prescription monitoring agency are "very high."

He said Nova Scotia doctors have to avoid prescribing large amounts of opioids unless there is clear medical evidence of their necessity, and it may be necessary to step up reviews of doctors who consistently are high prescribers.

"We've known this has been a problem for a long time ... why wasn't this acted on?" he asked.

"This is a very serious problem where regulators had a mandate to identify and act on very serious problems of medical practice and to a large extent that has not happened, though that's not limited to Nova Scotia," he said.

Dr. David Martell, a family doctor and addictions specialist based in Lunenburg, N.S., said the health risks from excessive dosages can be substantial and wide ranging.

"There's a risk of developing opioid use disorder, not to mention intolerable side effects such as changes in cognition, sedation, constipation, low libido and drug interactions," he wrote in an email.

He also said the large prescriptions increase the chances of the medicines being passed along to friends or family.