LONDON, ON – A new study from ICES, Lawson Health Research Institute and Western University suggests that injection drug users prescribed controlled-release hydromorphone are three times more likely to develop endocarditis, a serious bacterial heart infection, when compared to those prescribed other opioids. The findings, published today in The Lancet Infectious Diseases, build on growing evidence that some controlled-release opioids may lead to higher risk of infectious disease among persons who inject drugs.
The researchers looked at de-identified Ontario health data for hospital admissions related to injection drug use between 2006 and 2015. Of 60,529 admissions, 733 patients had infective endocarditis. The team found that regions with high hydromorphone prescription rates had more than double the cases of infective endocarditis (254 cases) when compared to regions with low prescription rates (113 cases).
The study also analyzed individual prescription records and found that among persons who inject drugs, those prescribed controlled-release hydromorphone were three times more likely to develop infective endocarditis when compared to those prescribed any other opioid. There was no increased risk for those prescribed the immediate-release form of hydromorphone.
“Added to the existing data, these findings make a compelling argument for the role of controlled-release hydromorphone in the growing risk of infective endocarditis among persons who inject drugs,” says Dr. Matthew Weir, Adjunct Scientist at ICES, Associate Scientist at Lawson and Assistant Professor at Western’s Schulich School of Medicine & Dentistry.
Opioids are often manufactured as controlled-release or ‘slow-release’ capsules to prevent rapid absorption of the drug. Properties in the capsules help to spread pain relief over a longer period of time.
This is the latest in a series of studies from the research team that suggest some controlled-release opioids may be leading to increased risk of infectious disease among persons who inject drugs.
In one study, they demonstrated that polymer-coated beads used to provide the slow-release property make controlled-release hydromorphone difficult to dissolve. They found equipment used to dissolve the drug retains up to 45 per cent of the initial dose, leading injection drugs users to save and reuse equipment.
With frequent re-handling of equipment, there are multiple opportunities for bacterial and viral contamination. The team found that HIV and a dangerous bacterium called Staphylococcus aureus are more likely to survive in equipment used to prepare controlled-release hydromorphone since added chemicals that make the drug slow-release promote survival of bacteria and viruses.
“There’s been a global increase in infectious diseases among persons who inject drugs and our research suggests that controlled-release prescription opioids may be a major culprit,” says Dr. Michael Silverman, Associate Scientist at Lawson and Associate Professor at Schulich Medicine & Dentistry. “We now have evidence that suggests the injection of controlled-release hydromorphone is increasing the spread of HIV, hepatitis C and endocarditis in Canada.”
The team believes these findings could also explain the increase in infectious complications in the USA and other countries where controlled-release hydromorphone is not on the market. There are other controlled-release opioids, such as controlled-release morphine, that use a similar slow-release mechanism and may carry similar risks.
“It’s important that people are aware of the infectious risks of injecting opioids and, if necessary, practice harm reduction techniques,” says Dr. Silverman. “We’ve found you can use a cigarette lighter to destroy bacteria and viruses by heating the cooker used to prepare the drug for about 10 seconds or until the mixture bubbles. We’ve termed the technique ‘cook your wash.’”
-30-
DOWNLOADABLE MEDIA
Equipment used by persons who inject drugs
Cooker with lighter (demonstrating the ‘Cook your wash’ technique)
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 health care issues. Our unbiased evidence provides measures of health system performance, a clearer understanding of the shifting health care 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
Lawson Health Research Institute is one of Canada’s top hospital-based research institutes, tackling the most pressing challenges in health care. As the research institute of London Health Sciences Centre and St. Joseph’s Health Care London, our innovation happens where care is delivered. Lawson research teams are at the leading-edge of science with the goal of improving health and the delivery of care for patients. Working in partnership with Western University, our researchers are encouraged to pursue their curiosity, collaborate often and share their discoveries widely. Research conducted through Lawson makes a difference in the lives of patients, families and communities around the world. To learn more, visit www.lawsonresearch.ca.
The Schulich School of Medicine & Dentistry at Western University is one of Canada’s preeminent medical and dental schools. Established in 1881, it was one of the founding schools of Western University and is known for being the birthplace of family medicine in Canada. For more than 130 years, the School has demonstrated a commitment to academic excellence and a passion for scientific discovery.
Senior Media Relations Consultant
Communications & Public Engagement
T: 519-685-8500 ext. 73502
Celine.zadorsky@lhsc.on.ca
