Case report: Local anesthesia with lidocaine infiltration for extended-release buprenorphine therapy.

Background: Extended-release buprenorphine (BUP-XR) is a once-monthly subcutaneous injection for the treatment of opioid use disorder. Injection-site pain is a common adverse event reported with BUP-XR administration. Notwithstanding the advantages of BUP-XR, subjective pain and anxiety associated with injections can compromise patients' willingness to receive treatment. Lidocaine is an amide-type agent and sodium channel blocker commonly used for local and regional anesthesia in various fields of medicine. Case presentation: We present two cases involving lidocaine infiltration to the induction phase of BUP-XR therapy in an outpatient setting. Prior to the intervention, 2 mL of 1% lidocaine was infiltrated subcutaneously at the sites of the planned needle insertion for a numbing effect. The following BUP-XR therapy was well tolerated by both participants and reported as a painless procedure. Conclusions: Lidocaine infiltration may be a feasible way to successfully initiate and provide BUP-XR therapy to those who may be deterred by injection-related risks. Our cases describe how lidocaine can be useful in mitigating injection-site pain and encouraging greater uptake, and in turn, greater retention in opioid agonist therapy.