Coformulations of buprenorphine and naloxone

Buprenorphine is available in a coformulation with naloxone (an opioid antagonist) as a sublingual preparation. The coformulation is designed to deter intravenous injection of sublingual buprenorphine.

If the coformulation is taken sublingually or orally, the naloxone component does not contribute to, or prevent, toxicity. However, if a patient with opioid-dependence dissolves and injects the coformulation, they can experience acute opioid withdrawal, followed by buprenorphine toxicity when the effect of naloxone wears off.