Why is Naloxone added to Buprenorphine?

December 8, 2022

Why is naloxone added to buprenorphine in oral or sublingual preparations? Both drugs are prescribed for opiate use disorder. Buprenorphine is prescribed because it binds to the same receptors as opiates such as morphine and heroin, but it partially blocks the receptors (anti-opioid) while at the same time having a mild opioid effect on it as well (opioid-agonist). Naloxone on the other hand is a complete opioid-antagonist (anti-opioid). 

When the buprenorphine-naloxone combination (Suboxone) is given as a sublingual (under the tongue) medication, only the buprenorphine is absorbed, whereas the naloxone has almost no effect as absorption is almost negligible. The reason naloxone is added is to prevent possible abuse of the medication, as there is a theoretical risk that some people may crush up the medication, dissolve it and try to inject it into their veins.

If patients inject a buprenorphine/naloxone combination in hopes of achieving euphoria, naloxone goes to work, binding to the opioid receptors, preventing a “high” and possibly even causing withdrawal symptoms. Combination buprenorphine/naloxone medications include Suboxone, Zubsolv, Bunavail, and Cassapaia. 

The mono-product of buprenorphine (Subutex) is rarely prescribed as first-line and is reserved for a small subset of patients only. In some states Subutex is even banned or heavily restricted.