Buprenorphine Depot Injections

Buprenorphine is now available as a depot injection for the maintenance treatment of opioid dependence. Two products are registered in Australia, Buvidal® and Sublocade®. However, only Buvidal® is currently accessible on the Pharmaceutical Benefits Scheme (PBS) having received a Section 100 Opioid Dependence listing on the 1^st September 2019.

Buvidal® is a modified-release buprenorphine injection for weekly (±2 days) or monthly (±1 week) administration. Upon contact with body fluids, the solution forms a highly viscous gel from which the active ingredient is released in a slow and consistent manner. Buvidal® should be injected slowly into the subcutaneous tissue, taking care to avoid inadvertent intravascular or intradermal injection. Patients may transition directly to Buvidal® from sublingual buprenorphine formulations. However, as the bioavailability of the depot is up to nine times higher than sublingual formulations, appropriate dosage adjustment is required.

A double-blind, double-dummy randomised clinical trial demonstrates non-inferiority of weekly and monthly depot buprenorphine compared to daily sublingual buprenorphine-naloxone. Further analysis establishes the superiority of depot buprenorphine with 35% of urine samples from these patients testing negative for illicit opioids compared to 28% of samples from patients receiving sublingual buprenorphine-naloxone. The safety profile of depot buprenorphine was comparable to that of sublingual buprenorphine-naloxone with the exception of some mild to moderate injection site reactions.

Anticipated benefits of depot buprenorphine injections include:

• Improved adherence;
• Greater convenience;
• Reduced stigma associated with supervised dosing;
• Reduced risk of diversion; and
• Reduced risk of inadvertent medication exposure (e.g. to children from takeaway doses).