Coadministration of glecaprevir/pibrentasvir (300/120 mg once daily) and buprenorphine/naloxone was studied in 12 subjects on individualized regimens of buprenorphine/naloxone. Dose normalized Cmax, AUC and C24 were slightly increased for buprenorphine (8%, 17% and 24%) and norbuprenorphine (25%, 30% and 21%). Naloxone dose-normalised Cmax and AUC were minimally affected (12% change or less). These changes were not considered clinically significant. Exposures of glecaprevir and pibrentasvir were similar to the observed values in previous studies. No dose adjustment is required.