Relative preferences in the abuse of immediate-release versus extended-release opioids in a sample of treatment-seeking opioid abusers

Purpose: Although differences in the pharmacological properties of immediate-release (IR) and extended-release (ER) opioid formulations have been reported, there are few studies comparing the real world abuse and relative preferences for these formulations. Methods: To examine drug preferences, we used a structured survey of 8304 individuals entering treatment (2011–2014) for opioid use disorder followed by a more focused online survey (2014–2015) with a subset of these patients (N = 301). Results: Our results demonstrated that both ER and IR opioids were frequently abused by those with an opioid use disorder in terms of lifetime (91.0% vs. 98.7%, respectively) or past month (46.1% vs. 67.4%, respectively) abuse, but given the choice, only 4% of the sample selected ER compounds as their preferred formulation. The remainder had no preference (29.9%) or a distinct preference for IR formulations (66.1%), regardless of route of administration—oral or non-oral (smoking/snorting or injecting). This preference for IR formulations seems to be related to: (i) the perceived immediacy and quality of the high (73.0%) from IR products; and (ii) they were easier to use, particularly when manipulated for non-oral abuse, than ER products (31.2%). Conclusions: Based on these results, while most abusers have experience with both formulations, there is a greater preference for IR formulations, compared to ER, regardless of route of administration. As a result, it may not be unreasonable to suggest that supply-side initiatives to restrict the diversion and abuse of prescription opioids may be just as important for both IR and ER opioids.