Whether use during pregnancy is safe is unclear, but use while breastfeeding is probably safe, since the dose the infant receives is 1-2% that of the maternal dose, on a weight basis.Buprenorphine was patented in 1965, and approved for medical use in the United States in 1981. It is on the World Health Organizations List of Essential Medicines. In addition to prescription as an analgesic it is  a common medication used to treat opioid use disorders, such as addiction to heroin. In 2017, 14.6 million prescriptions for the medication were written in the United States. Buprenorphine may also be used recreationally for the high it produces, and in the US sublingual formulations are marketed as a film or mixed with naloxone to discourage injection. In the United States, buprenorphine is a schedule III controlled substance. Medical uses
Opioid use disorder
Buprenorphine is used to treat people with opioid use disorder. : 84–7  In the U.S., the combination formulation of buprenorphine/naloxone is generally prescribed to deter injection, since naloxone, an opioid antagonist, causes acute withdrawal if the formulation is crushed and injected. : 99  However, taken orally, the nalaxone has virtually no effect, due to the drugs extremely high first-pass metabolism and low bioavailability (2%). Before starting buprenorphine, individuals are generally advised to wait long enough after their last dose of opioid until they have some withdrawal symptoms to allow for the medication to bind the receptors,since if taken too soon, buprenorphine can displace other opioids bound to the receptors and precipitate an acute withdrawal.
Pharmacology
Pharmacodynamics
Opioid receptor modulator
Buprenorphine has been reported to possess these following pharmacological activities:
μ-Opioid receptor (MOR): Very high affinity partial agonist: at low doses, the MOR-mediated effects of buprenorphine are comparable to those of other narcotics, but these effects reach a "ceiling" as the receptor population is saturated. This behavior is responsible for several unique properties: buprenorphine greatly reduces the effect of most other MOR agonists, can cause precipitated withdrawal when used in actively opioid dependent persons, and has a lower incidence of respiratory depression and fatal overdose relative to full MOR agonists. κ-Opioid receptor (KOR): High affinity antagonist—this activity is hypothesized to underlie some of the effects of buprenorphine on mood disorders and addiction. δ-Opioid receptor (DOR): High affinity antagonist
Nociceptin receptor (NOP, ORL-1): Weak affinity, very weak partial agonistIn simplified terms, buprenorphine can essentially be thought of as a nonselective, mixed agonist–antagonist opioid receptor modulator, acting as an unusually high affinity weak partial agonist of the MOR, a high affinity antagonist of the KOR and DOR, and a relatively low affinity, very weak partial agonist of the ORL-1/NOP.Although buprenorphine is a partial agonist of the MOR, human studies have found that it acts like a full agonist with respect to analgesia in opioid-intolerant individuals.