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.
Buprenorphine was patented in 1965 and approved for medical use in the United States in 1981. In 2017, 14.6 million prescriptions for the medication were written in the United States. It is also a common drug of abuse, being used in place of heroin. Buprenorphine may be used recreationally by injection or in the nose for the high it produces. In the United States it is a Schedule IIIcontrolled 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, was approved in the United States in 2018.
Buprenorphine versus methadone
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.
Butrans patches in the pouch with packaging. A removed patch is shown on the left.
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.
A 2007 assessment of harm from recreational drug use (mean physical harm and mean dependence liability). Buprenorphine was ranked 9th in dependence, 8th in physical harm, and 11th in social harm.
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.
Allergic contact dermatitis from buprenorphine patch (few days after removal)
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.
Buprenorphine treatment carries the risk of causing psychological or physical dependence. Buprenorphine has a slow onset and a long half-life of 24 to 60 hours. Once a person has stabilized on the medication, there are three options: continual use, switching to buprenorphine/naloxone, or medically supervised withdrawal.
It is difficult to achieve acute opioid analgesia in persons using buprenorphine for opioid replacement therapy.
μ-Opioid receptor (MOR): Partial agonist. Binds with high affinity, but only partially activates the receptor. This property allows buprenorphine to act similarly to full opioid agonists at lower doses (mainly in non-tolerant individuals), reaching a ceiling/plateau at higher doses after which there is no further increase in typical opioid effects (therapeutic or recreational). This behavior is responsible for buprenorphine's ability to block most MOR agonists and the phenomenon of precipitated withdrawal when used in actively opioid dependent persons.
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 non-opioid-tolerant individuals. Conversely, buprenorphine behaves like a partial agonist of the MOR with respect to respiratory depression.
One of the major active metabolites of buprenorphine is norbuprenorphine, which, in contrast to buprenorphine itself, is a full agonist of the MOR, DOR, and ORL-1, and a partial agonist at the KOR. However, relative to buprenorphine, norbuprenorphine has extremely little antinociceptive potency (1/50th that of buprenorphine), but markedly depresses respiration (10-fold more than buprenorphine). This may be explained by very poor brain penetration of norbuprenorphine due to a high affinity of the compound for P-glycoprotein. In contrast to norbuprenorphine, buprenorphine and its glucuronide metabolites are negligibly transported by P-glycoprotein.
The glucuronides of buprenorphine and norbuprenorphine are also biologically active, and represent major active metabolites of buprenorphine.Buprenorphine-3-glucuronide has affinity for the MOR (Ki = 4.9 pM), DOR (Ki = 270 nM) and ORL-1 (Ki = 36 µM), and no affinity for the KOR. It has a small antinociceptive effect and no effect on respiration. Norbuprenorphine-3-glucuronide has no affinity for the MOR or DOR, but does bind to the KOR (Ki = 300 nM) and ORL-1 (Ki = 18 µM). It has a sedative effect but no effect on respiration.
Buprenorphine is a semi-synthetic analogue of thebaine and is fairly soluble in water, as its hydrochloride salt. It degrades in the presence of light.
Detection in body fluids
Buprenorphine and norbuprenorphine may be quantitated in blood or urine to monitor use or abuse, confirm a diagnosis of poisoning, or assist in a medicolegal investigation. There is a significant overlap of drug concentrations in body fluids within the possible spectrum of physiological reactions ranging from asymptomatic to comatose. Therefore, it is critical to have knowledge of both the route of administration of the drug and the level of tolerance to opioids of the individual when results are interpreted.
In 1969, researchers at Reckitt & Colman (now Reckitt Benckiser) had spent 10 years attempting to synthesize an opioid compound "with structures substantially more complex than morphine [that] could retain the desirable actions whilst shedding the undesirable side effects". Physical dependence and withdrawal from buprenorphine itself remain important issues since buprenorphine is a long-acting opioid. Reckitt found success when researchers synthesized RX6029 which had showed success in reducing dependence in test animals. RX6029 was named buprenorphine and began trials on humans in 1971. By 1978, buprenorphine was first launched in the UK as an injection to treat severe pain, with a sublingual formulation released in 1982.
In the years prior to buprenorphine/naloxone's approval, Reckitt Benckiser had lobbied Congress to help craft the Drug Addiction Treatment Act of 2000 (DATA 2000), which gave authority to the Secretary of Health and Human Services to grant a waiver to physicians with certain training to prescribe and administer Schedule III, IV, or V narcotic drugs for the treatment of addiction or detoxification. Prior to the passage of this law, such treatment was not permitted in outpatient settings except for clinics designed specifically for drug addiction.
The waiver, which can be granted after the completion of an eight-hour course, is required for outpatient treatment of opioid addiction with buprenorphine. Initially, the number of people each approved physician could treat was limited to ten. This was eventually modified to allow approved physicians to treat up to a hundred patients with buprenorphine for opioid addiction in an outpatient setting. This limit was increased by the Obama administration, raising the number of patients to which doctors can prescribe to 275. Still, due to this patient limit and the requisite eight-hour training course, many continuing patients can find it very difficult to get a prescription, despite the drug's effectiveness.
In the European Union, Subutex and Suboxone, buprenorphine's high-dose sublingual tablet preparations, were approved for opioid addiction treatment in September 2006. In the Netherlands, buprenorphine is a List II drug of the Opium Law, though special rules and guidelines apply to its prescription and dispensation.
Buprenorphine is available under the trade names Cizdol, Suboxone (with naloxone), Subutex (typically used for opioid addiction), Zubsolv, Bunavail, Sublocade, Probuphine, Temgesic (sublingual tablets for moderate to severe pain), Buprenex (solutions for injection often used for acute pain in primary-care settings), Norspan and Butrans (transdermal preparations used for chronic pain).
Buprenorphine has been introduced in most European countries as a transdermal formulation (marketed as Transtec) for the treatment of chronic pain not responding to non-opioids.
It has veterinary medical use for treatment of pain in dogs and cats.
In combination with samidorphan or naltrexone (μ-opioid receptor antagonists), buprenorphine is under investigation for the treatment of cocaine dependence, and recently demonstrated effectiveness for this indication in a large-scale (n = 302) clinical trial (at a high buprenorphine dose of 16 mg but not a low dose of 4 mg).
Buprenorphine has been used in the treatment of the neonatal abstinence syndrome, a condition in which newborns exposed to opioids during pregnancy demonstrate signs of withdrawal. Use currently is limited to infants enrolled in a clinical trial conducted under an FDA approved investigational new drug (IND) application. An ethanolic formulation used in neonates is stable at room temperature for at least 30 days.
^Mendelson J, Upton RA, Everhart ET, Jacob P 3rd, Jones RT (1997). "Bioavailability of sublingual buprenorphine". Journal of Clinical Pharmacology. 37 (1): 31–7. doi:10.1177/009127009703700106. PMID9048270.
^White; et al. (13 December 2017). "The efficacy and adverse effects of buprenorphine in acute pain management: a systematic review and meta-analysis of randomised controlled trials". British Journal of Anaesthesia. 120 (4): 668–678. doi:10.1016/j.bja.2017.11.086. PMID29576108.
^Roth, BL; Driscol, J. "PDSP Ki Database". Psychoactive Drug Screening Program (PDSP). University of North Carolina at Chapel Hill and the United States National Institute of Mental Health. Retrieved 14 August 2017.
^ abcToll L, Berzetei-Gurske IP, Polgar WE, Brandt SR, Adapa ID, Rodriguez L, Schwartz RW, Haggart D, O'Brien A, White A, Kennedy JM, Craymer K, Farrington L, Auh JS (1998). "Standard binding and functional assays related to medications development division testing for potential cocaine and opiate narcotic treatment medications". NIDA Res. Monogr. 178: 440–66. PMID9686407.
^Mizoguchi H, Wu HE, Narita M, et al. (2002). "Antagonistic property of buprenorphine for putative epsilon-opioid receptor-mediated G-protein activation by beta-endorphin in pons/medulla of the mu-opioid receptor knockout mouse". Neuroscience. 115 (3): 715–21. doi:10.1016/s0306-4522(02)00486-4. PMID12435410.
^Mizoguchi H, Spaulding A, Leitermann R, Wu HE, Nagase H, Tseng LF (July 2003). "Buprenorphine blocks epsilon- and micro-opioid receptor-mediated antinociception in the mouse". J. Pharmacol. Exp. Ther. 306 (1): 394–400. doi:10.1124/jpet.103.048835. PMID12721333.
^Yassen A, Kan J, Olofsen E, Suidgeest E, Dahan A, Danhof M (2007). "Pharmacokinetic-pharmacodynamic modeling of the respiratory depressant effect of norbuprenorphine in rats". The Journal of Pharmacology and Experimental Therapeutics. 321 (2): 598–607. doi:10.1124/jpet.106.115972. PMID17283225.
^Huang P, Kehner GB, Cowan A, Liu-Chen LY (2001). "Comparison of pharmacological activities of buprenorphine and norbuprenorphine: Norbuprenorphine is a potent opioid agonist". The Journal of Pharmacology and Experimental Therapeutics. 297 (2): 688–695. PMID11303059.
^Claude, Andrew (June 2015). "Buprenorphine"(PDF). cliniciansbrief.com. Retrieved 25 February 2017.
^Kukanich, Butch; Papich, Mark G. (14 May 2013). "Opioid Analgesic Drugs". In Jim E. Riviere, Mark G. Papich (ed.). Veterinary Pharmacology and Therapeutics (9 ed.). John Wiley & Sons. pp. 323–325. ISBN9781118685907.
^Stanciu, CN; Glass, OM; Penders, TM (April 2017). "Use of Buprenorphine in treatment of refractory depression-A review of current literature". Asian Journal of Psychiatry. 26: 94–98. doi:10.1016/j.ajp.2017.01.015. PMID28483102.
^Ragguett, RM; Rong, C; Rosenblat, JD; Ho, RC; McIntyre, RS (April 2018). "Pharmacodynamic and pharmacokinetic evaluation of buprenorphine + samidorphan for the treatment of major depressive disorder". Expert Opinion on Drug Metabolism & Toxicology. 14 (4): 475–482. doi:10.1080/17425255.2018.1459564. PMID29621905.