Because of its opioid agonist effects, buprenorphine is abusable, particularly by individuals who are not physically addicted to opioids. Naloxone is added to buprenorphine to decrease the likelihood of diversion and abuse of the combination product. Sublingual buprenorphine has moderate bioavailability, while sublingual naloxone has poor bioavailability. Thus, when the buprenorphine/naloxone tablet is taken in sublingual form, the buprenorphine opioid agonist effect predominates, and the naloxone does not precipitate opioid withdrawal in the opioid-addicted user.
Naloxone via the parenteral route, however, has good bioavailability. If the sublingual buprenorphine/naloxone tablets are crushed and injected by an opioid-addicted individual, the naloxone effect predominates and can precipitate the opioid withdrawal syndrome.
Under certain circumstances buprenorphine by itself can also precipitate withdrawal in opioid-addicted individuals. This is more likely to occur with higher levels of physical addiction, with short time intervals (e.g., less than 2 hours) between a dose of opioid agonist (e.g., methadone) and a dose of buprenorphine, and with higher doses of buprenorphine.