Why is naloxone added to buprenorphine in oral or sublingual preparations? Both drugs are prescribed for opioid use disorder. Buprenorphine is prescribed because it binds to the same receptors as opioids 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, the buprenorphine is readily absorbed, whereas the naloxone is not and therefore has almost no effect. The reason naloxone is added is to prevent misuse of the medication, as there is a risk that some people may crush up the medication, dissolve it, and try to inject it.
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 causing withdrawal symptoms. Combination buprenorphine/naloxone medications include Suboxone, Zubsolv, and Bunavail.
The mono-product of buprenorphine (Subutex) is rarely prescribed and is reserved for a small subset of patients. In some states Subutex is even banned or heavily restricted.