Sublingual buprenorphine-naloxone precipitated withdrawal-A case report with review of literature and clinical considerations.

Buprenorphine- Naloxone Fixed Dose Combination (BNX) is widely used to manage opioid use disorders. Contrary to evidence based concepts about sublingual bio-availability of naloxone, a few small studies have reported non-negligible amounts absorbed sublingually. But the extent to which these amounts exert opioid antagonist effects is yet to be established. We hereby report the first case of opioid dependence who developed a rare phenomenon of moderate to severe opioid withdrawal symptoms on administration of sublingual BNX after several days of being stabilized on plain buprenorphine (BUP). The case demonstrates the need to consider using buprenorphine monotherapy whenever such adverse effects are encountered. We also discuss the possible pharmacological explanations behind this rare side effect.