The FDA has approved a subcutaneously injected, extended-release formulation of the mu-opioid receptor partial agonist and kappa-opioid receptor antagonist buprenorphine (Brixadi – Braeburn) for once-weekly or once-monthly treatment of moderate to severe opioid use disorder. Brixadi is the second subcutaneously injected buprenorphine formulation to be approved in the US; Sublocade, which is administered once monthly, was the first. Buprenorphine is also available for treatment of opioid use disorder in sublingual formulations with and without the opioid antagonist...