People who inject drugs (PWID) and are prescribed controlled-release hydromorphone are 3 times more likely to develop endocarditis compared with those prescribed other opioids, according to a study published in The Lancet Infectious Diseases.

Researchers at the Lawson Health Research Institute and Western University analyzed at de-identified Ontario health data for hospital admissions related to injection drug use between 2006 and 2015. Of 60,529 admissions, 733 individuals had infective endocarditis.

The research team found that regions with high hydromorphone prescription rates had approximately double the cases of infective endocarditis (254 cases) compared with regions with low prescription rates (113 cases), according to a press release.

The study also analyzed individual prescription records and found that among PWID, those prescribed controlled-release hydromorphone were 3 times more likely to develop infective endocarditis compared with 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,” said Matthew Weir, MD, adjunct scientist at the Institute for Clinical Evaluative Sciences, in the press release.

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. Some controlled-release opioids may lead to an increased risk of infectious disease among PWID, according to the press release.

Previous research has found that polymer-coated beads used to provide the slow-release property make controlled-release hydromorphone difficult to dissolve. Equipment used to dissolve the drug retains up to 45% of the initial dose, leading PWID to save and reuse equipment.

With frequent re-handling of equipment, there are opportunities for bacterial and viral contamination. HIV and Staphylococcus aureus are more likely to survive in equipment used to prepare controlled-release hydromorphone because added chemicals that make the drug slow-release promote survival of bacteria and viruses.

These findings could explain the increase in infectious complications in the United States as well as other countries in which controlled-release hydromorphone is not on the market, according to the study. Other controlled-release opioids, such as controlled-release morphine, may carry similar risks.

Reference
Controlled-release opioid may be leading to heart infections in persons who inject drugs [news release] London, ON. January 22, 2020. https://www.lawsonresearch.ca/controlled-release-opioid-leading-to-infections. Accessed January 29, 2020.