Safety profile of injectable hydromorphone and diacetylmorphine for long-term severe opioid use disorder.

Aims: To review the safety profile of injectable hydromorphone and diacetylmorphine and explore if adverse events (AEs) or serious adverse events (SAEs) were associated with dose and patterns of attendance.

Methods: This was a non-inferiority randomized double-blind controlled trial (Vancouver, Canada) testing hydromorphone (n=100) and diacetylmorphine (n=102) for the treatment of severe opioid use disorder. Medications were delivered under the supervision of trained Registered Nurses up to three times daily. AEs were described using MedDRA codes.

Results: Most common related AEs included immediate post-injection reaction or injection site pruritus reactions, somnolence and opioid overdoses. Adjusted analysis indicated that participants in the hydromorphone group were less likely to have any related AE or SAE compared to the diacetylmorphine group. Related somnolence and opioid overdose events were distributed throughout the six months treatment period. In the diacetylmorphine group, five of the eleven related SAE opioid overdoses (requiring naloxone) occurred in the first 30days since most recent treatment initiation. Analysis of somnolence and opioid overdose (AEs and SAEs) event rates by received dose suggested a non-linear relationship. However, in the diacetylmorphine group higher event rates per person days were recorded at lower doses.

Conclusions: When injectable hydromorphone and diacetylmorphine are individually dosed and monitored, their opioid-related side effects, including potential fatal overdoses, are safely mitigated and treated by health care providers. In the midst of an opioid overdose epidemic, injectable options are timely to reach a very important minority of people who inject street opioids and are not attracted to other treatments.