The number of opioid prescriptions has continued to rise in Canada despite a national epidemic of drug overdoses, according to a new study which bolsters criticisms that doctors are overprescribing highly addictive painkillers.

The number of opioid prescriptions rose from 20.2 million in 2012 to 21.5 million in 2016, said the study published on Wednesday by the Canadian Institute for Health Information (CIHI), a non-profit research group.

Canada is the world’s second-biggest consumer of pharmaceutical opioids and experts said the new data underlines a “serious issue” of overprescription, which has impacted addiction rates.

Six opioids — codeine, tramadol, oxycodone, hydromorphone, morphine, and fentanyl (the latter four are considered especially strong) — accounted for more than 96 percent of all opioids prescribed in the study period.

Wednesday’s study follows another report from CIHI, which found that hospitalizations and emergency department visits related to opioid poisoning are also rising in Canada.

More than 2,800 people died of apparent opioid overdoses in 2016, and at least 602 Canadians died in the first quarter of 2017, according to the Public Health Agency of Canada.

“While we are rightly paying close attention to overdose deaths, we need to be looking at a broader range of outcomes: emergency room visits, hospitalizations and prescribing across all age groups,” said Robert Strang, Nova Scotia’s chief medical officer said in a statement released with the study. “If you put together the rates of prescribing with some of the hospitalization data, it shows we have a serious issue in Canada.”

The number of patients being prescribed opioids that are considered “strong” has increased from 52 to 57 percent.

New guidelines

The overprescription of painkillers is often cited by experts as a major factor in the fentanyl overdose crisis responsible for thousands of deaths nationwide. The amount of fentanyl being prescribed by doctors has resulted in many patients becoming dependent and feeling they need increasingly higher doses. And some of that prescription fentanyl has ended on the streets, rather than in medicine cabinets in a trend linked to increased prescriptions.

While the number of opioid doses rose nationwide, the quantity of opioids dispensed to Canadians, measured by the average daily dose for an adult, dropped, said the study.

Researchers characterized the reduced daily doses as a positive development: lower quantities encourage doctors and patients to interact more frequently. This, in turn, allows health care providers to monitor how well a drug is working and whether or not the patient needs to keep taking it.

Many doctors started prescribing drugs like fentanyl and hydromorphone after OxyContin, once Canada’s best-selling long-acting opioid, was taken off shelves in 2012, following a rise in reports of abuse and addiction. OxyContin had been aggressively marketed by its maker Purdue Pharmaceuticals as a non-addictive and effective for non-cancer-related pain.

Experts are hopeful that new guidelines on opioid prescriptions released in May will discourage doctors from prescribing opioids as a first-line of treatment for patients with chronic, non-cancer pain, and to opt instead for other kinds of treatments, including non-pharmaceutical therapies.