Buprenorphine conversion and pharmacology
Used for chronic pain (lower doses) and medication-assisted treatment (MAT) for OUD (higher doses).
Equianalgesic estimate
Conversion varies significantly by formulation and indication.
Published equianalgesic ratios vary between references and with clinical context. Read how to interpret conversion results before applying an estimate.
Mechanism of action
Partial agonist at the mu-opioid receptor (high affinity, low intrinsic activity) and antagonist at the kappa-opioid receptor.
Brand names: Butrans (TD), Belbuca (Buccal), Subutex (SL), Sublocade (SC), Suboxone (w/ Naloxone)
Pharmacokinetics
- Protein binding
- ~96%
- Volume of distribution
- ~2.5 L/kg
- Half-life
- 24-42 hours (Sublingual); ~26 hours (after transdermal removal).
| Route | Form | Bioavailability | Onset | Peak | Duration |
|---|---|---|---|---|---|
| Sublingual | SL | 30-50% | 30-60 min | 1-4 hours | 6-12+ hours (dose-dependent) |
| Buccal | — | 46-65% | — | — | — |
| Transdermal | TD | — | 12-24 hours | ~60 hours | Varies (e.g., 7 days for Butrans) |
Metabolism
- CYP3A4 (N-dealkylation)
- Glucuronidation (UGT1A1, UGT2B7)
Metabolites
- Norbuprenorphine Active metabolite; weaker analgesic than parent drug, but a potent respiratory depressant.
High affinity and slow dissociation from the mu-receptor. Susceptible to CYP3A4 inhibitors/inducers.
Renal and hepatic impairment
Renal
Considered one of the safest opioids in renal failure. Primarily fecal excretion of metabolites. Dose adjustments generally not needed.
Hepatic
Mild/Moderate: Use caution. Severe: Dose reduction may be needed as clearance is reduced.
Clinical cautions
- Ceiling effect for respiratory depression (in absence of other CNS depressants) and analgesia.
- Can precipitate withdrawal in patients physically dependent on full agonists due to high affinity.
- Risk of QTc prolongation, especially at higher doses.
For qualified healthcare professionals. This page is an educational reference, not prescribing advice. Check medicine information and conversion factors against a current clinical source and local guidance.
Other opioids in this reference
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Last updated 30 August 2026. Read how to interpret conversion results and the Terms of Service.