Buprenorphine

Buprenorphine, sold under the brand name Subutex among others, is an opioid used to treat opioid use disorder, acute pain, and chronic pain. It can be used under the tongue (sublingual), in the cheek (buccal), by injection (intravenous and subcutaneous), as a skin patch (transdermal), or as an implant. For opioid use disorder, the patient must have moderate opioid withdrawal symptoms before buprenorphine can be administered under direct observation of a health-care provider.

In the United States, the combination formulation of buprenorphine/naloxone (Suboxone) is usually prescribed to discourage misuse by injection. However, more recently the efficacy of naloxone in preventing misuse has been brought into question, and preparations of buprenorphine combined with naloxone could potentially be less safe than buprenorphine alone. Maximum pain relief is generally within an hour with effects up to 24 hours. Buprenorphine affects different types of opioid receptors in different ways. Depending on the type of opioid receptor, it may be an agonist, partial agonist, or antagonist. Buprenorphine's activity as an agonist/antagonist is important in the treatment of opioid use disorder: it relieves withdrawal symptoms from other opioids and induces some euphoria, but also blocks the ability for many other opioids, including heroin, to cause an effect. Unlike full agonists like heroin or methadone, buprenorphine has a ceiling effect, such that taking more medicine past a certain point will not increase the effects of the drug.

Side effects may include respiratory depression (decreased breathing), sleepiness, adrenal insufficiency, QT prolongation, low blood pressure, allergic reactions, constipation, and opioid addiction. Among those with a history of seizures, a risk exists of further seizures. Opioid withdrawal following stopping buprenorphine is generally less severe than with other opioids. 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 Organization's 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 2020, it was the 186th most commonly prescribed medication in the United States, with more than 2.8 million prescriptions. Buprenorphine may also be used recreationally for the high it can produce. In the United States, buprenorphine is a schedule III controlled substance.