Buprenorphine is a semi-synthetic opioid

Opioid

An opioid is a psychoactive chemical that works by binding to opioid receptors, which are found principally in the central and peripheral nervous system and the gastrointestinal tract...

 that is used to treat opioid addiction in higher dosages (>2 mg), to control moderate acute pain

Pain

Pain is an unpleasant sensation often caused by intense or damaging stimuli such as stubbing a toe, burning a finger, putting iodine on a cut, and bumping the "funny bone."...

 in non-opioid tolerant individuals in lower dosages (~200 µg), and to control moderate chronic pain

Chronic pain

Chronic pain has several different meanings in medicine. Traditionally, the distinction between acute and chronic pain has relied upon an arbitrary interval of time from onset; the two most commonly used markers being 3 months and 6 months since the initiation of pain, though some theorists and...

 in dosages ranging from 20-70 µg/hour.

Buprenorphine is one of the Bentley compounds

Bentley compounds

Bentley compounds are a class of semi-synthetic opioids that were first synthesized from thebaine by K. W. Bentley. The compounds include: oxycodone, oxymorphone, nalbuphine, naloxone, naltrexone, buprenorphine and etorphine. They represent the first series of more potent μ-opioid agonists, with...

 derived from an alkaloid

Alkaloid

Alkaloids are a group of naturally occurring chemical compounds that contain mostly basic nitrogen atoms. This group also includes some related compounds with neutral and even weakly acidic properties. Also some synthetic compounds of similar structure are attributed to alkaloids...

 of the plant Papaver somniferum (the opium poppy), known as thebaine

Thebaine

Thebaine , its name coming from the Greek Θῆβαι, Thēbai, an ancient city in Upper Egypt, is an opiate alkaloid. A minor constituent of opium, thebaine is chemically similar to both morphine and codeine, but has stimulatory rather than depressant effects, causing convulsions similar to strychnine...

.

Buprenorphine has an extremely high binding affinity at the µ

Mu Opioid receptor

The μ-opioid receptors are a class of opioid receptors with high affinity for enkephalins and beta-endorphin but low affinity for dynorphins. They are also referred to as μ opioid peptide receptors. The prototypical μ receptor agonist is the opium alkaloid morphine; μ refers to morphine...

- and κ-opioid receptor

Kappa Opioid receptor

The κ-opioid receptor is a protein that in humans is encoded by the OPRK1 gene. The κ-opioid receptor is one of five related receptors that bind opium-like compounds in the brain and are responsible for mediating the effects of these compounds...

.