[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Opioids and antagonists](https://durgical.com/en/pharmacology/classes/opioids-and-antagonists/) › Buprenorphine

[Pharmacology](https://durgical.com/en/pharmacology/) · [Opioids and antagonists](https://durgical.com/en/pharmacology/classes/opioids-and-antagonists/)

# Buprenorphine

A high-affinity partial μ agonist with a ceiling on respiratory depression. It treats opioid use disorder and pain; it can precipitate withdrawal.

Updated 2026-11-01

- Class: [Opioids and antagonists](https://durgical.com/en/pharmacology/classes/opioids-and-antagonists/)
- Receptor: μ-opioid receptor (partial agonist; also acts at κ, δ and nociceptin receptors)
- ATC code: N02AE01

## ⚠ High-alert medication

An error with this medicine can cause serious harm: double checks and protocols are used.

◎**μ-opioid receptor (partial agonist; also acts at κ, δ and nociceptin receptors)**Buprenorphine

ⓘ The figure shows morphine, a full agonist, in the μ receptor; buprenorphine occupies the same site. There is no structure of buprenorphine in the receptor.

**Target in 3D:** μ-opioid receptor (partial agonist; also acts at κ, δ and nociceptin receptors). PDB structure 8EF6 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/8EF6) · Drag to rotate · pinch to zoom

## Mechanism of action

Buprenorphine is a partial μ-receptor agonist: it binds with very high affinity and leaves very slowly, but activates the receptor only partly. So it has a ceiling effect on respiratory depression, displaces full agonists (and can precipitate withdrawal in people using them), and naloxone reverses its established effects only with difficulty. It also acts at κ, δ and nociceptin receptors.

- Binds the μ receptor with high affinity and leaves very slowly
- Activates it only partly: a ceiling effect on breathing
- Displaces full agonists and blocks their effect
- Less craving and withdrawal, with lower overdose risk

## Pharmacokinetics

**Absorption**
Sublingual or buccal; swallowed, much of its effect is lost.

**Metabolism**
Liver, with a major role for CYP3A4.

**Onset and duration**
Its clinical effect does not track blood levels because it leaves the receptor slowly; after stopping, withdrawal appears late.

## Indications

- Opioid use disorder (induction and maintenance), as part of a plan with psychosocial support
- Pain needing an opioid (injectable and transdermal forms)

## Adverse effects

### Common

- Headache
- Nausea, vomiting and constipation
- Sweating
- Insomnia
- Withdrawal symptoms at the start

### Serious (rare, important)

- Life-threatening respiratory depression, above all at the start or after a dose increase
- Addiction, abuse and misuse, with risk of overdose and death
- Neonatal opioid withdrawal syndrome with prolonged use in pregnancy
- Adrenal insufficiency with prolonged use
- Precipitated withdrawal if started while a full agonist is still on the receptor
- Hepatitis and other liver events
- Tooth decay and tooth loss with sublingual and buccal forms

## Contraindications

- Hypersensitivity to buprenorphine

## Key interactions

**Benzodiazepines, alcohol and other central nervous system depressants**
Add up to profound sedation, respiratory depression, coma and death.

**CYP3A4 inhibitors**
Raise buprenorphine levels.

**Full opioid agonists**
Buprenorphine displaces full agonists and can precipitate withdrawal or weaken their pain relief.

## What is monitored

- Objective signs of withdrawal before the first dose
- Liver function tests before and during treatment
- Sedation and breathing, above all with other depressants
- Dental health

## Administration and safety

- The tablet is placed under the tongue until it dissolves; it is not cut, chewed or swallowed.
- Nothing is eaten or drunk until it has fully dissolved; then the teeth and gums are rinsed with a sip of water.
- The first dose is given only when clear signs of withdrawal are present, so as not to precipitate it.
- Controlled medicine: the order is verified, every dose recorded and leftovers kept secure.

## Nursing care

- Assess withdrawal with an objective scale before starting.
- Teach the sublingual technique and the rinse afterwards because of the risk of tooth decay.
- Keep naloxone available for the patient and family because of the risk of relapse and overdose.
- Watch sedation and breathing, above all if combined with benzodiazepines or alcohol.
- Review liver tests and ask about jaundice or dark urine.

## Pregnancy and breastfeeding

It is used in pregnancy to treat opioid use disorder (without naloxone in some regimens); the newborn may develop neonatal opioid withdrawal syndrome.

## Memory aid

BUPRENORPHINE = «the stubborn tenant»: moves into the μ receptor, won't leave (high affinity), does only half the job (partial agonist) and throws the others out (precipitates withdrawal).

## Test yourself

Think of the answer, then tap the question to see it.

## Why does buprenorphine carry less risk of fatal respiratory depression than morphine?

Because it is a partial μ agonist: its effect on breathing has a ceiling even as the dose rises (unless other depressants are added).

## Why can buprenorphine precipitate withdrawal, and when is it started to avoid that?

It displaces the full agonist from the receptor and activates it less; it is started only once the patient shows clear signs of withdrawal.

## Why does naloxone reverse established buprenorphine effects only with difficulty?

Because of buprenorphine's high affinity and very slow release from the μ receptor.

## What dental care is taught with sublingual buprenorphine?

After it dissolves, take a sip of water, swish it around the teeth and gums and swallow, because of reports of severe decay and tooth loss.

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## Related drugs

- [Methadone](https://durgical.com/en/pharmacology/methadone/)
- [Naloxone](https://durgical.com/en/pharmacology/naloxone/)
- [Naltrexone](https://durgical.com/en/pharmacology/naltrexone/)

[← Back to the class: Opioids and antagonists](https://durgical.com/en/pharmacology/classes/opioids-and-antagonists/)

Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.

Sources: [Buprenorphine Sublingual (opioid dependence): MedlinePlus Drug Information](https://medlineplus.gov/druginfo/meds/a626094.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [BUPRENORPHINE HYDROCHLORIDE tablet](https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=442831cf-9636-433a-9a12-e9a8cd31f72a) (DailyMed (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 23 (McGraw Hill, 2023); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=N02AE01) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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