April 28, 2010 in Employee Drug Testing Information
Buprenorphine is an opioid partial agonist. This means that, although buprenorphine is an opioid, and thus can produce typical opioid agonist effects and side effects such as euphoria and respiratory depression, its maximal effects are less than those of full agonists like heroin and methadone. At low doses buprenorphine produces sufficient agonist effect to enable opioid-addicted individuals to discontinue the misuse of opioids without experiencing withdrawal symptoms. The agonist effects of buprenorphine increase linearly with increasing doses of the drug until at moderate doses they reach a plateau and no longer continue to increase with further increases in dose—the “ceiling effect.” Thus, buprenorphine carries a lower risk of abuse, addiction, and side effects compared to full opioid agonists. In fact, in high doses and under certain circumstances, buprenorphine can actually block the effects of full opioid agonists and can precipitate withdrawal symptoms if administered to an opioid-addicted individual while a full agonist is in the bloodstream.
Buprenorphine has poor oral bioavailability and moderate sublingual bioavailability. Formulations for opioid addiction treatment are in the form of sublingual tablets.
Buprenorphine is highly bound to plasma proteins. It is metabolized by the liver via the cytochrome P4503A4 enzyme system into norbuprenorphine and other metabolites. The half-life of buprenorphine is 24–60 hours.