Injection drug users prescribed controlled release hydromorphone—an opioid—are three times more likely to develop endocarditis than users prescribed other opioids, according to work published Jan. 22 in The Lancet Infectious Diseases.
For the study, Michael Silverman, MD, and colleagues at ICES, the Lawson Health Research Institute and Western University looked at de-identified heart data from hospital admissions related to injection drug use between 2006 and 2015 in Ontario, Canada. Of the 60,529 admissions they included in their dataset, 733 patients presented with infective endocarditis, a serious bacterial heart infection.
Silverman et al. noted that regions with higher hydromorphone prescription rates saw more than double the cases of infective endocarditis compared to regions with lower hydromorphone prescription rates—254 cases versus 113 cases. Individual prescription records revealed that injection drug users prescribed controlled-release hydromorphone were three times more likely to develop endocarditis than their peers prescribed other opioids.
Patients prescribed immediate-release hydromorphone didn’t see the same increased risk, the authors said, suggesting drugs that are manufactured as controlled-release or slow-release might present an issue for certain people. Controlled-release capsules were developed to prevent rapid absorption of drugs and prolong pain relief for an extended period of time, but Silverman and colleagues said they found the polymer-coated beads used to provide that slow-release property make controlled-release hydromorphone harder to dissolve.
In that study, which was separate from their current work, Silverman’s team found that equipment used to dissolve the slow-release drug retained up to 45% of the initial dose, which could lead injection drug users to save and reuse equipment. And the more equipment that’s handled, the higher the chance of bacterial and viral contamination.
“It’s important that people are aware of the infectious risks of injecting opioids and, if necessary, practice harm reduction techniques,” Silverman said in a release. “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.’”
The researchers’ past work, combined with their newest findings, suggest some controlled-release opioids may be hiking the risk of infectious disease among injection drug users.
“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,” Silverman said. “We now have evidence that suggests the injection of controlled-release hydromorphone is increasing the spread of HIV, hepatitis C and endocarditis in Canada.”