Buprenorphine is the maintenance treatment of choice for most patients with opioid use disorder. To prevent severe opioid withdrawal, patients must already be receiving treatment with buprenorphine or undergo a trial with a short-acting transmucosal product before a long-acting formulation can be initiated.2 The labeling changes allow for a first subcutaneous dose of Sublocade to be given after a single transmucosal test dose of buprenorphine; previously, use of transmucosal buprenorphine for at least 7 days had been required. The new labeling also allows for Sublocade to be administered into the abdomen, thigh, buttock, or back of the upper arm; previously, it could only be injected into the abdomen.

Brixadi, another subcutaneous, extended-release formulation of buprenorphine, is already indicated for use following only a single test dose of transmucosal buprenorphine (see Table 1).3 

Approval of the new Sublocade dosage regimen was based on the results of an open-label trial (available only as an abstract) in which 140 patients were randomized 2:1 to receive Sublocade after either a single dose of transmucosal buprenorphine (rapid induction) or 7-14 days of transmucosal treatment (standard induction). The rate of treatment retention at the time of the second injection (1 week after the initial injection), the primary endpoint, was noninferior with rapid induction compared to standard induction (67.1% vs 59.6%). Rates of precipitated opioid withdrawal were similar in the rapid and standard induction groups (16.9% vs 14.6%).4 

How Sublocade and Brixadi compare to one another in efficacy is unknown. Use of a long-acting subcutaneous formulation of buprenorphine should reduce the risks of treatment nonadherence and drug diversion, but it is considerably more expensive than sublingual formulations.2