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Combined use of opioids and gabapentin substantially increases risk of overdose


Ontario patients co-prescribed gabapentin and opioids were 49 per cent more likely to suffer an opioid-related death than patients prescribed opioids alone, a new study has found.

Gabapentin is a drug used to treat chronic pain and is often prescribed in conjunction with opioids. Despite gabapentin generally being perceived as safe, co-prescription of opioids and gabapentin is known to increase the amount of these drugs absorbed by the body and the way in which these drugs affect the central nervous system. Both drugs have also been shown to suppress breathing, which can be fatal.

The study, being published today in PLOS Medicine, is the first to investigate whether co-prescription of opioids and gabapentin is associated with an increased risk of accidental opioid-related mortality.

“Our findings show that combined use of opioids and gabapentin is common with nearly half of all gabapentin users were being co-prescribed an opioid in 2013,” says senior author Dr. Tara Gomes, a scientist at the Institute for Clinical Evaluative Sciences (ICES), the Li Ka Shing Knowledge Institute of St. Michael’s Hospital and a principal investigator of the Ontario Drug Policy Research Network.

Using administrative health-care databases housed at ICES, Gomes’ team identified residents of Ontario between the ages of 15 to 104 who were eligible for drug coverage under the Ontario Drug Benefit Program between April 1, 1997 and December 31, 2013. The researchers looked at opioid users who died of an opioid-related cause. Among the findings:

  • Overall, 12.3 per cent of cases (155 people) were co-prescribed opioids and gabapentin
  • The risk of an opioid-related death was 49 per cent higher among patients recently exposed to gabapentin and opioids compared to those exposed to opioids alone
  • Exposure to moderate or high doses of gabapentin was associated with a nearly 60 per cent increase of opioid-related death compared to opioids alone

“These findings are important for clinicians and patients alike. Clinicians need to consider these risks when prescribing a combination of opioids and gabapentin and if both drugs are absolutely necessary, they should consider adjusting doses to avoid the risk of accidental overdose,” says Gomes. “Furthermore, patients need to be aware of the potential respiratory risks when taking these drugs simultaneously.”

“Gabapentin, opioids and the risk of opioid-related death: a population-based nested case-control study,” was published today in PLOS Medicine.

Author block: Tara Gomes, David N. Juurlink, Tony Antoniou, Muhammad M. Mamdani, J. Michael Paterson and Wim van den Brink.

The Institute for Clinical Evaluative Sciences (ICES) is an independent, non-profit organization that uses population-based health information to produce knowledge on a broad range of healthcare issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting healthcare needs of Ontarians, and a stimulus for discussion of practical solutions to optimize scarce resources. ICES knowledge is highly regarded in Canada and abroad, and is widely used by government, hospitals, planners, and practitioners to make decisions about care delivery and to develop policy. For the latest ICES news, follow us on Twitter: @ICESOntario

About St. Michael’s Hospital

St Michael’s Hospital provides compassionate care to all who enter its doors. The hospital also provides outstanding medical education to future healthcare professionals in 27 academic disciplines. Critical care and trauma, heart disease, neurosurgery, diabetes, cancer care, care of the homeless and global health are among the Hospital’s recognized areas of expertise. Through the Keenan Research Centre and the Li Ka Shing International Healthcare Education Centre, which make up the Li Ka Shing Knowledge Institute, research and education at St. Michael’s Hospital are recognized and make an impact around the world. Founded in 1892, the hospital is fully affiliated with the University of Toronto.

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