Buprenorphine/naloxone, sold under the brand name Suboxone among others, is a fixed-dose combination medication that includes buprenorphine and

naloxone Naloxone, sold under the brand names Narcan (4 mg) and Kloxxado (8 mg) among others, is a medication used to reverse or reduce the effects of opioids. It is commonly used to counter decreased breathing in opioid overdose. Effects begin withi ...

. It is used to treat opioid use disorder, and reduces the mortality of opioid use disorder by 50% (by reducing the risk of overdose on full-agonist opioids such as heroin or

fentanyl Fentanyl, also spelled fentanil, is a very potent synthetic opioid used as a pain medication. Together with other drugs, fentanyl is used for anesthesia. It is also used illicitly as a recreational drug, sometimes mixed with heroin, cocain ...

). It relieves cravings to use and withdrawal symptoms. Buprenorphine/naloxone is available for use in two different forms, under the tongue or in the cheek. Side effects may include respiratory depression (decreased breathing),

small pupils Miosis, or myosis (), is excessive constriction of the pupil.Farlex medical dictionary
citing: ...

, sleepiness, and low blood pressure. The risk of overdose with buprenorphine/naloxone (unless combined with other sedating substances) is exceedingly low, and lower than with methadone, but people are more likely to stop treatment on buprenorphine/naloxone than methadone. Buprenorphine (like methadone) is a treatment option during pregnancy. At lower doses, buprenorphine results in the usual

opioid Opioids are substances that act on opioid receptors to produce morphine-like effects. Medically they are primarily used for pain relief, including anesthesia. Other medical uses include suppression of diarrhea, replacement therapy for opioid use ...

effects; high doses beyond a certain level do not result in greater effects. This is believed to result in a lower risk of overdose than some other opioids. Naloxone is an opioid antagonist that competes with and blocks the effect of other opioids (including buprenorphine) if given by injection. Naloxone is poorly absorbed when taken by mouth and is added to decrease the risk that people will misuse the medication by injection. Misuse by injection or use in the nose still occurs. Rates of misuse in the U.S. appear to be lower than with other opioids. The combination formulation was approved for medical use in the U.S. in 2002, and in the European Union in 2017. A

generic version A generic drug is a pharmaceutical drug that contains the same chemical substance as a drug that was originally protected by chemical patents. Generic drugs are allowed for sale after the patents on the original drugs expire. Because the active c ...

was approved in the U.S. in 2018. In 2019, it was the 272nd most commonly prescribed medication in the U.S., with more than 1million prescriptions.

Medical uses

Buprenorphine/naloxone is used for the treatment of opioid use disorder. Long-term outcomes are generally better with use of buprenorphine/naloxone than attempts at stopping opioid use altogether. This includes a lower risk of overdose with medication use. Due to the high binding affinity and low activation at the opioid receptor, cravings and withdrawal for opioids are decreased while preventing a person from getting high and relapsing on another opioid. The combination of the two medications is preferred over buprenorphine alone for maintenance treatment due to the presence of naloxone in the formulation, which helps discourage intravenous use. Buprenorphine/naloxone has been found to be effective for treating opioid dependence, and serves as a recommended first-line medication according to the U.S. National Institute on Drug Abuse. The medication is an effective maintenance therapy for opioid dependence and has generally similar efficacy to methadone. Both buprenorphine/naloxone and are substantially more effective than abstinence-based treatment. Prescribers need a Drug Addiction Treatment Act (DATA 2000) waiver to prescribe buprenorphine/nalaxone for opioid dependence. Because it may be prescribed out of an office setting (as opposed to methadone, which requires specialized centers), buprenorphine/naloxone allows people more freedom of administration. It also thus comes with more risks in this vulnerable population. Buprenorphine/naloxone may be recommended for socially stable people who use opioids who cannot retrieve medications from a center daily, who have another condition requiring regular primary care visits, or who have jobs or daily lives that require they maintain all their faculties and cannot take a sedating medication. Buprenorphine/naloxone is also recommended over methadone for people who at high risk of methadone toxicity, such as the elderly, those taking high doses of benzodiazepines or other sedating substances, concomitant alcohol use disorder, those with a lower level of opioid tolerance, and those at high risk of

prolonged QT interval Long QT syndrome (LQTS) is a condition affecting repolarization (relaxing) of the heart after a heartbeat, giving rise to an abnormally lengthy QT interval. It results in an increased risk of an irregular heartbeat which can result in fainting, ...

. It is also helpful to use the medication in combination with psychosocial support and counseling.

Available forms

Buprenorphine/naloxone is available in sublingual formulations (that is, products that are dissolved under the tongue). There is no evidence that the tablet formulation is easier to divert and use in ways other than intended by the prescriber compared to the film formulation, or that the tablet formulation has a higher risk for accidental ingestion by children. There are various pharmacokinetic differences between sublingual formulations.

Contraindications

Contraindications are severe respiratory or liver impairment and acute

alcoholism Alcoholism is, broadly, any drinking of alcohol that results in significant mental or physical health problems. Because there is disagreement on the definition of the word ''alcoholism'', it is not a recognized diagnostic entity. Predomi ...

. There are limited accounts of cross-reactivity with opioids, but there is a possibility. Serious

central nervous system The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain and spinal cord. The CNS is so named because the brain integrates the received information and coordinates and influences the activity of all p ...

(CNS) and

respiratory depression Hypoventilation (also known as respiratory depression) occurs when ventilation is inadequate (''hypo'' meaning "below") to perform needed respiratory gas exchange. By definition it causes an increased concentration of carbon dioxide (hypercapni ...

may also occur with concurrent use of CNS depressants, ingesting alcohol, or other CNS-depressing factors while on buprenorphine/naloxone.

Adverse effects

Side effects are similar to those of buprenorphine and other opioids. In addition, naloxone can induce withdrawal symptoms in people who are chemically dependent on opioids. The most common side effects (in order of most to least common) of sublingual tablets include headaches, opioid withdrawal syndrome, pain, nausea, increased sweating, and

difficulty sleeping Insomnia, also known as sleeplessness, is a sleep disorder in which people have trouble sleeping. They may have difficulty falling asleep, or staying asleep as long as desired. Insomnia is typically followed by daytime sleepiness, low energy, ...

. The most common side effects seen in film formulations are tongue pain, decreased sensation and redness in the mouth, headache, nausea, vomiting,

excessive sweating Hyperhidrosis is a condition characterized by abnormally increased sweating, in excess of that required for regulation of body temperature. Although primarily a benign physical burden, hyperhidrosis can deteriorate quality of life from a psychologi ...

constipation Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel moveme ...

, signs and symptoms of opioid withdrawal, sleeping difficulties, pain, and swelling of the extremities. Buprenorphine/naloxone has a milder side effect profile than methadone and limited respiratory effects, due to both agonist/antagonist effects. But buprenorphine/naloxone may be less safe than methadone in people with stable liver disease, since it can elevate liver enzymes.

Dependence and withdrawal

When taken in excess, buprenorphine/naloxone can produce dysphoric symptoms for non opioid-dependent/tolerant people because buprenorphine is a partial opioid agonist. The sublingual formulation of the buprenorphine/naloxone combination was designed to reduce the potential to inject the medication in comparison to buprenorphine alone. If the combination is taken sublingually, as directed, the addition of naloxone does not diminish buprenorphine's effects. When an opioid-dependent person dissolves and injects a combination sublingual tablet, a withdrawal effect may be triggered because of naloxone's high parenteral bioavailability. While this mechanism can act to deter intravenous injection, the Suboxone formulation can still produce an opioid agonist "high" if used sublingually by non-dependent persons, leading to opioid dependence.Clinical Guidelines for the Use of Buprenorphine in the Treatment of Opioid Addiction
Treatment Improvement Protocol (TIP) 40. Laura McNicholas. US Department of Health and Human Services.

Interactions

Buprenorphine's sedating/narcotic effect is increased by other sedating substances, such as other opioids, benzodiazepines, first-generation antihistamines, alcohol, and

antipsychotic Antipsychotics, also known as neuroleptics, are a class of psychotropic medication primarily used to manage psychosis (including delusions, hallucinations, paranoia or disordered thought), principally in schizophrenia but also in a range of ...

s. Opioids and especially benzodiazepines also increase the risk of potentially lethal

. Strong inhibitors of the liver enzyme

CYP3A4 Cytochrome P450 3A4 (abbreviated CYP3A4) () is an important enzyme in the body, mainly found in the liver and in the intestine. It oxidizes small foreign organic molecules ( xenobiotics), such as toxins or drugs, so that they can be removed from ...

, such as

ketoconazole Ketoconazole, sold under the brand name Nizoral among others, is an antiandrogen and antifungal medication used to treat a number of fungal infections. Applied to the skin it is used for fungal skin infections such as tinea, cutaneous ca ...

, moderately increase buprenorphine concentrations; CYP3A4 inducers can theoretically decrease concentrations of buprenorphine.

Pharmacology

Buprenorphine-naloxone action at opioid receptor

Buprenorphine is a Partial Agonist at the µ-Opioid Receptor

Mechanism of action

Buprenorphine binds strongly to opioid receptors and acts as a pain-reducing medication in the

(CNS). It binds to the

μ-opioid receptor The μ-opioid receptors (MOR) are a class of opioid receptors with a high affinity for enkephalins and beta-endorphin, but a low affinity for dynorphins. They are also referred to as μ(''mu'')-opioid peptide (MOP) receptors. The prototypical ...

with high affinity, which produces the analgesic effects in the CNS. It is a partial μ-opioid receptor agonist and a weak

κ-opioid receptor The κ-opioid receptor or kappa opioid receptor, abbreviated KOR or KOP, is a G protein-coupled receptor that in humans is encoded by the ''OPRK1'' gene. The KOR is coupled to the G protein Gi/G0 and is one of four related receptors that bind ...

antagonist. As the dose of buprenorphine increases, its analgesic effects reach a plateau, and then it starts to act like an antagonist. As a

partial agonist In pharmacology, partial agonists are drugs that bind to and activate a given receptor, but have only partial efficacy at the receptor relative to a full agonist. They may also be considered ligands which display both agonistic and antagonis ...

, buprenorphine binds and activates the opioid receptors, but has only partial efficacy at the receptor relative to a full agonist, even at maximal receptor occupancy. It is thus well-suited to treat opioid dependence, as it produces milder effects on the opioid receptor with lower dependence and habit-forming potential. Naloxone is a pure opioid antagonist that competes with opioid molecules in the CNS and prevents them from binding to the opioid receptors. Naloxone's

binding affinity In biochemistry and pharmacology, a ligand is a substance that forms a complex with a biomolecule to serve a biological purpose. The etymology stems from ''ligare'', which means 'to bind'. In protein-ligand binding, the ligand is usually a mo ...

is highest for the μ-opioid receptor, then the δ-opioid receptor, and lowest for the κ-opioid receptor. Naloxone has poor bioavailability, and is rapidly inactivated following oral administration. When injected, it exerts its full effects. The principle behind its function as a deterrent is as follows: when taken sublingually as prescribed, buprenorphine's effects at the opioid receptor dominate, while naloxone's effects are negligible due to the low oral absorption. But when someone attempts to misuse the medication via either injection or inhalation, the naloxone is intended to act as an antagonist and either reduce the opioid's euphoric effects or even precipitate withdrawal in those dependent on opioids. This helps reduce the potential for deviating from the prescriber's intended use relative to buprenorphine, though it does not eradicate it. One reason that naloxone might have limited efficacy as an abuse deterrent is that buprenorphine binds more tightly to the mu-opioid receptor than naloxone.

Pharmacokinetics

There are small differences in the pharmacokinetics between different sublingual buprenorphine/naloxone products. These differences may require changes in dose when a person switches from one product to another. The buprenorphine/naloxone sublingual film (e.g. trade name Suboxone) achieves higher buprenorphine maximum plasma concentrations (C_max) and area under the curve (AUC, a measure of total drug exposure) than the original buprenorphine/naloxone sublingual tablets at equal doses. For example, at a buprenorphine/naloxone dose of 8 mg/2 mg, the buprenorphine C_max after a single dose of the original tablet formulation is around 3 ng/mL whereas that of the 8 mg/2 mg film formulation is around 3.55 ng/mL. The Zubsolv trade name sublingual tablets have higher buprenorphine bioavailability than the original sublingual tablets, while the Bunavail trade name buccal films have the highest bioavailability. For example, a single dose of Bunavail 4.2 mg/0.7 mg achieves a C_max around 3.41 ng/mL.

Buprenorphine

Buprenorphine is

metabolized Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...

by the

liver The liver is a major organ only found in vertebrates which performs many essential biological functions such as detoxification of the organism, and the synthesis of proteins and biochemicals necessary for digestion and growth. In humans, it i ...

, primarily via the

cytochrome P450 Cytochromes P450 (CYPs) are a superfamily of enzymes containing heme as a cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are important for the clearance of various co ...

(CYP) isozyme

, into norbuprenorphine. The

glucuronidation Glucuronidation is often involved in drug metabolism of substances such as drugs, pollutants, bilirubin, androgens, estrogens, mineralocorticoids, glucocorticoids, fatty acid derivatives, retinoids, and bile acids. These linkages involve gl ...

of buprenorphine is primarily carried out by the UDP-glucuronosyltransferases (UGTs) UGT1A1 and UGT2B7, while norbuprenorphine is glucuronidated by UGT1A1 and UGT1A3. These glucuronides are then eliminated mainly through

excretion Excretion is a process in which metabolic waste is eliminated from an organism. In vertebrates this is primarily carried out by the lungs, kidneys, and skin. This is in contrast with secretion, where the substance may have specific tasks after ...

into

bile Bile (from Latin ''bilis''), or gall, is a dark-green-to-yellowish-brown fluid produced by the liver of most vertebrates that aids the digestion of lipids in the small intestine. In humans, bile is produced continuously by the liver (liver bi ...

. The

elimination half-life Biological half-life (also known as elimination half-life, pharmacologic half-life) is the time taken for concentration of a biological substance (such as a medication) to decrease from its maximum concentration ( Cmax) to half of Cmax in the b ...

of buprenorphine is 20 to 73 hours (mean 37 hours). Due to the mainly hepatic elimination, there is no risk of accumulation in people with kidney problems.

Naloxone

Naloxone is extensively inactivated by first-pass metabolism in the liver, meaning that use of buprenorphine/naloxone as prescribed should not lead to active naloxone in the blood (which, as an opioid antagonist, would reverse the effect of buprenorphine or other opioids).

Society and culture

Cost

While the cost of the medication buprenorphine/naloxone is greater than buprenorphine alone, one analysis predicted the overall costs would be less in the United States due to a lower risk of misuse.

Access in the United States

Before the Drug Addiction Treatment Act of 2000 (DATA), physicians were not allowed to prescribe narcotics to treat opioid dependence. People with narcotic dependence had to go to registered clinics to receive treatment. With DATA, Suboxone was the first medication approved for office-based treatment for opioid dependence. Suboxone has thus become widely used as a replacement for methadone as it can be prescribed by doctors in their offices, while methadone can only be provided at specialized addiction centers, of which there are a limited number, often making access difficult. Integrating Medication-Assisted Treatment into outpatient primary care practices improves patient access to Suboxone. Some physicians are also leading a movement to begin prescribing it out of the emergency department (ED), as some small studies have shown ED-initiated Suboxone to be effective with people more likely to remain in addiction treatment compared to those either referred to addiction treatment programs or those receiving just a brief intervention in the department. Access to Suboxone can be limited due to varying

prior authorization Prior authorization is a utilization management process used by some health insurance companies in the United States to determine if they will cover a prescribed procedure, service, or medication. The process is intended to act as a safety and co ...

requirements across different insurers. Prior authorization is used by insurance companies to limit certain medications' use by requiring approval before the insurance company will pay for them. This can influence a person's financial access and adherence. Financial access is determined through prior authorization approval, which the prescriber must request before the person can start the medication. The time it takes to have the request approved can delay the person in starting the medication. The prior authorization process can also affect adherence, because the approval is needed for every prescription. This presents the potential for a gap in treatment and withdrawal symptoms as the person waits for approval. Several insurance companies, as well as

Medicaid Medicaid in the United States is a federal and state program that helps with healthcare costs for some people with limited income and resources. Medicaid also offers benefits not normally covered by Medicare, including nursing home care and per ...

in various states, have removed the use of prior authorization for Suboxone in an attempt to increase access to this treatment.

Controversies

In July 2019, the British company Reckitt Benckiser Group (RB Group) and its current/former affiliated entities (notably Indivior, which split from RB Group in 2014) settled with the US Department of Justice (DOJ) regarding the sale and marketing of brand name Suboxone (buprenorphine/naloxone). The non-prosecution agreement involves RB Group paying up to $1.4 billion, the largest settlement payment in U.S. history involving an opioid-class medication. This record was surpassed in October 2020, when Purdue Pharma reached an $8 billion settlement for claims related to injuries and deaths caused by the opioid epidemic, which includes criminal fines, forfeiture, and civil damages. The 2019 case alleged

anti-competitive Anti-competitive practices are business or government practices that prevent or reduce competition in a market. Antitrust laws differ among state and federal laws to ensure businesses do not engage in competitive practices that harm other, usuall ...

behavior by RB Group and Indivior surrounding the expiration of their regulatory exclusivity for Suboxone sublingual tablets. The DOJ alleged that RB Group and Indivior employed a "product hopping" scheme (when a firm ceases production of a product upon expiration of regulatory exclusivity in favor of another product that still has regulatory exclusivity in order to prevent generic manufacturer competition) by misrepresenting that the Suboxone sublingual film formulation was safer than the sublingual tablet formulation because "children are less likely to be accidentally exposed to the film product". There was no scientific evidence for that claim. The company also sponsored a complaint to the FDA, expressing concern that buprenorphine/naloxone sublingual tablets (the very product they formerly produced) were unsafe, requesting that applications for regulatory approval of generic products by other pharmaceutical companies (their competitors) be rejected by the US

Food and Drug Administration The United States Food and Drug Administration (FDA or US FDA) is a federal agency of the Department of Health and Human Services. The FDA is responsible for protecting and promoting public health through the control and supervision of food ...

References

External links

* {{DEFAULTSORT:Buprenorphine Naloxone Combination drugs Drug rehabilitation 4,5-Epoxymorphinans Kappa-opioid receptor antagonists Merck & Co. brands Mu-opioid receptor agonists Mu-opioid receptor antagonists Oripavines Wikipedia medicine articles ready to translate Schering-Plough brands Semisynthetic opioids Orphan drugs