People who inject drugs may be less likely to inject buprenorphine-naloxone than other opioid substitutes, according to the results of a recent study published in the Medical Journal of Australia.
Buprenorphine is used to treat heroin dependence. It is longer-acting than methadone, which is the most common treatment in Australia, so fewer doses are required and overdose is less likely; but problems with injecting of buprenorphine have been documented in Australia and other countries, with major injection-related complications of concern. An alternative form of the medication - buprenorphine-naloxone - was developed to deter injection. If injected by a person who is opioid-dependent, buprenorphine-naloxone can cause unpleasant withdrawal symptoms. Until recently, there has been minimal evidence in Australia, or internationally, that this approach to the problem was effective. First results from a study monitoring whether buprenorphine-naloxone is related to lower levels of injection were published today in the MJA.
Professor Louisa Degenhardt, doctoral candidate, Ms Briony Larance (National Drug and Alcohol Research Centre at the University of New South Wales), and their colleagues, studied data collected from interviews across Australian capital cities with thousands of people who inject drugs regularly. Among drug injectors who were not
in treatment, levels of weekly buprenorphine-naloxone injection (3%) were significantly lower than they were for buprenorphine (8%). This was despite buprenorphine-naloxone being more widely used across Australia. The authors suggested that this reflected a lower attractiveness of this formulation for injection among people who inject drugs.
Nonetheless, injection of buprenorphine-naloxone is still occurring, including among patients in treatment. The authors were careful to point out that across all areas of medicine, patients often fail to take medications in the way they are meant to.
"It's risky, but it shows that for some clients, injecting remains a strongly preferred way of taking medication. This raises the question of whether there is a patient group for whom injecting itself really is difficult to overcome. We need to think outside the square," Ms Larance said.
"In the current treatment context in Australia, it seems clear that buprenorphine-naloxone is not as attractive as buprenorphine for injection - among those being treated with the drug, and on the illicit "street" market. The upside of this is that buprenorphine-naloxone is typically being prescribed most flexibly in Australia: with less supervised dosing, the extent to which drug use and treatment impact upon daily life can be greatly reduced," Prof Degenhardt said.
"Although this new medication allows us to be more confident about the safety of opioid treatment, drug formulations can't replace good clinical practice and psychosocial support".
The Medical Journal of Australia
is a publication of the Australian Medical Association.