Buprenorphine

Buprenorphine, sold under the brand name Subutex, among others, is an opioid used to treat opioid addiction, acute pain, and chronic pain. It can be used under the tongue, by injection, as a skin patch, or as an implant. For opioid addiction it is typically only started when withdrawal symptoms have begun and for the first two days of treatment under direct observation of a health care provider. For longer term treatment of addiction a combination formulation of buprenorphine/naloxone (Suboxone) is recommended to discourage misuse by injection. Maximum pain relief is generally within an hour with effects up to 24 hours. Side effects may include respiratory depression (decreased breathing), sleepiness, adrenal insufficiency, QT prolongation, low blood pressure, allergic reactions, and opioid addiction. Among those with a history of seizures, there is a risk of further seizures. Opioid withdrawal following stopping buprenorphine is generally less severe than with other opioids. It is unclear if use during pregnancy is safe and use while breastfeeding is not recommended. Buprenorphine affects different types of opioid receptors in different ways. Depending on the type of receptor it may be an agonist, partial agonist, or antagonist. Buprenorphine was patented in 1965 and approved for medical use in the United States in 1981. In 2012, 9.3 million prescriptions for the medication were written in the United States. Buprenorphine may also be used recreationally by injection or in the nose for the high it produces. Occasionally it is used recreationally instead of heroin. In the United States it is a Schedule III controlled substance. For the tablets the wholesale cost in the United States is between US$0.86 and US$1.32 per daily dose as of 2017. Its primary use is for the initial treatment of those with opioid addiction. It should only be started once symptoms of withdrawal have begun. For longer term treatment of addiction a combination formulation of buprenorphine/naloxone is usually recommended. A once a month injection, sold under the brandname Sublocade, has been approved in the United States and it should be available in 2018. Both buprenorphine and methadone are medications used for detoxification, short- and long-term opioid replacement therapy. Effectiveness of buprenorphine and methadone appear similar, with similar side effects. A transdermal patch is available for the treatment of chronic pain. These patches are not indicated for use in acute pain, pain that is expected to last only for a short period of time, or pain after surgery, nor are they recommended for opioid addiction. Common adverse drug reactions associated with the use of buprenorphine are similar to those of other opioids and include: nausea and vomiting, drowsiness, dizziness, headache, memory loss, cognitive and neural inhibition, perspiration, itchiness, dry mouth, shrinking of the pupils of the eyes (miosis), orthostatic hypotension, male ejaculatory difficulty, decreased libido, and urinary retention. Constipation and CNS effects are seen less frequently than with morphine. The most severe side effect associated with buprenorphine is respiratory depression (insufficient breathing). It occurs more often in those who are also taking benzodiazepines, alcohol, or have underlying lung disease. The usual reversal agents for opioids, such as naloxone, may be only partially effective and additional efforts to support breathing may be required. Respiratory depression may be less than with other opioids, particularly with chronic use. However, in the setting of acute pain management, buprenorphine appears to cause the same rate of respiratory depression as other opioids such as morphine.