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Prescriptions for high dose opioids on rise in Canada, study finds


September 15, 2014
By Sheryl Ubelacker The Canadian Press

Sept. 15, 2014 – Prescriptions for high-dose formulations of opioids like oxycodone and morphine jumped significantly in Canada between 2006 and 2011, despite guidelines advising doctors against giving such elevated doses to most patients, a study has found.

Researchers at St. Michael's Hospital in Toronto and the Institute for
Clinical Evaluative Sciences found the rate of high-dose opioid
dispensing across Canada increased 23 per cent during the six-year
study, from 781 units per 1,000 people in 2006 to 961 units in 2011.

Put
another way, that's almost one high-dose opioid pill or patch for every
person across Canada, say the researchers, who reported their findings
Friday in the journal Canadian Family Physician.

“We found that
high-dose prescribing was widespread across the country, but the
prevalence differed considerably between provinces,” said lead author
Tara Gomes.

Dispensing rates in Saskatchewan and Newfoundland and
Labrador spiked dramatically, rising almost 85 per cent and 54 per
cent, respectively; Alberta, up six per cent, and British Columbia,
rising eight per cent, remained relatively stable.

Ontario had
the highest dispensing rate at 1,382 units per 1,000 people – more than
one per resident – while Quebec had the lowest rate at 368 units per
1,000 people.

Provinces also differed in which opioids were most
often prescribed. In Alberta and Ontario, oxycodone was the top choice,
while B.C. doctors most commonly prescribed morphine.

Gomes said
there are a couple of factors likely driving the provincial differences
in which of the highly addictive painkillers doctors choose to
prescribe.

“One could be variations in how these drugs are
covered on public drug programs,” she said. “We know that in some
provinces like Ontario and Alberta, they didn't have very many
restrictions on access to oxycodone at the time of the study… and
those are the provinces where we see the higher rates of prescribing of
high-dose oxycodone.”

In B.C. and Newfoundland and Labrador, for
example, hydromorphone was a restricted product and those provinces have
some of the lowest rates of that drug at high doses.

Different
marketing strategies by manufacturers may also have fed into increased
dispensing rates of certain products in some provinces, Gomes suggested.
For instance, Ontario's large population may have led to more
aggressive promotion of newer opioids like oxycodone compared to
jurisdictions with smaller populations.

“So in those provinces
you might see older agents where clinicians historically have been more
comfortable prescribing an older drug like morphine, for example, and
they passed that on through training of residents and newer clinicians,”
she said.

The study found the per capita rate of high-dose
opioid dispensing increased steadily in Canada between 2006 and 2008
before plateauing in 2009-2010, coinciding with the release of Canadian
guidelines and a study showing that the rate of fatal opioid overdoses
had increased dramatically in Canada.

Those guidelines designate
opioid doses equivalent to 200 milligrams of morphine per day as
“watchful doses,” and doctors are advised to carefully consider the
potential risks of addiction and overdose before prescribing a dose that
exceeds that threshold.

“The evidence shows that these drugs can
be effective for treating acute pain conditions for a short period,”
said Gomes, citing pain suffered by cancer patients as an example.

“Where
the evidence is not as clear is whether these are really an effective
pain-management option for long-term use” for treating such problems as
chronic low back pain or knee pain, she said.

Research has shown
that high-dose opioids can lead to overdoses and death, motor vehicle
accidents and falls that cause serious fractures.

“These are the
very potent, high-dose pills,” said Gomes. “If somebody who's never
taken an opioid before ingests one of these high-dose tablets, they
could overdose just by taking one or two of these tablets because of the
strength of the product.”

Their potency is a risk for both
patients prescribed the medications and recreational users who procure
them on the street, she said.

Canada and the United States have
the highest levels of prescription opioid use in the world. On average,
more than 30 million high-dose tablets or patches are dispensed in
Canada each year.

More than 180 million units were dispensed
across Canada from 2006 to 2011, the study found. Almost half were
oxycodone, followed by morphine, hydromorphone and fentanyl patches.

“On
a national front, I think that we likely need a unified response to
this opioid issue because we're seeing that across Canada there are high
rates of use of these products,” said Gomes.

But variations in
the provinces, particularly in the type of these drugs being dispensed,
suggests that a unified approach must be tailored to individual
jurisdictions because a program that works in one province may not work
in another, she said.