Buprenorphine
Buprenorphine hydrochloride
Also known as: Buprenex · Subutex · Suboxone · Butrans · Temgesic · Simbadol · Zorbium · Bupaq · Buprecare · Buprenodale · Buprevet · Vetergesic · Buprenorphine HCl · buprenorphini hydrochloridum · CL-112302 · NIH-8805 · UM-952 · Buprenorphinum
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Audited v13 dosing evidence
Structured calculator evidenceAnalgesia during gastrointestinal stasis
Verified clinician required
- q8–12h
Governing clinical context (1)
- Exclude emergent diagnoses (obstruction, enterotoxemia)
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Buprenorphine is a highly versatile, widely used opiate partial agonist in veterinary medicine. It is primarily utilized for the management of mild to moderate acute pain, particularly in small animals, and is often incorporated into short-term immobilization 'cocktails' alongside alpha-2 agonists and dissociatives.
- Clinical Pearl: Buprenorphine exhibits a "ceiling effect" at standard doses, meaning that escalating the dose beyond a certain point may not yield additional analgesia and could theoretically decrease analgesic efficacy.
- Feline Advantage: Cats have a relatively alkaline oral pH, which renders buprenorphine highly lipophilic and allows for excellent oral transmucosal (OTM) / buccal absorption. In cats, buccal administration is nearly as bioavailable as an intramuscular injection, making it a highly practical route for at-home post-operative pain management.
- Duration: It has a longer onset of action compared to pure mu-agonists (like fentanyl or methadone) but provides a significantly longer duration of analgesia (typically 6-8 hours, up to 12 hours).
- Regulatory: It is a DEA Schedule III controlled substance.
Mechanism of action
Buprenorphine exerts its analgesic effects by acting as a partial agonist at the mu (μ) opioid receptor and an antagonist at the kappa (κ) opioid receptor in the central nervous system.
- High Affinity, Slow Dissociation: It binds to the μ-receptor with an affinity approximately 30 times greater than morphine. This tight binding → prolonged duration of action.
- Receptor Competition: Because of its high affinity, it can displace pure μ-agonists from the receptor, potentially antagonizing their analgesic effects while reversing their sedative and respiratory depressant effects.
- Naloxone Resistance: Its slow dissociation from the receptor makes it notoriously difficult to fully reverse with standard doses of the opioid antagonist naloxone; high doses of naloxone or the use of doxapram may be required in cases of severe respiratory depression.
Safety & warnings
Contraindications
- Known hypersensitivity to buprenorphine
Adverse effects
- Respiratory depression (rare but significant)
- Sedation
- Urine retention or difficulty voiding (particularly with high IV or epidural doses)
- Excitement (horses)
- Diminished gut sounds (horses)
- Vomiting (rare in cats)
Precautions
Use with caution in patients with hypothyroidism, severe renal insufficiency, adrenocortical insufficiency (Addison's), and in geriatric or severely debilitated patients. Use cautiously in patients with compromised cardiopulmonary function due to the rare risk of respiratory depression. Extreme caution is required in patients with head trauma, increased CSF pressure, or CNS dysfunction (e.g., coma). Patients with severe hepatic dysfunction may eliminate the drug more slowly. May increase bile duct pressure; use cautiously in biliary tract disease.
Drug interactions
May be potentiated by concomitant use of buprenorphine
May decrease plasma buprenorphine levels
Case reports of humans developing respiratory/cardiovascular/CNS depression; use with caution
May cause increased CNS or respiratory depression when used with buprenorphine
Can increase plasma buprenorphine levels
Buprenorphine may potentially antagonize some analgesic effects, but may also reverse some sedative and respiratory depressant effects
Potentially can increase buprenorphine effects
Can increase plasma buprenorphine levels
Possible additive effects or increased CNS depression
May reduce analgesia associated with high dose buprenorphine
If used with buprenorphine may cause increased conjunctival changes
Potentially decrease plasma buprenorphine concentrations
May antagonize the effects of full opioid agonists, though clinical relevance is debated. If analgesia is inadequate after buprenorphine, a full mu agonist may be administered without delay.
May antagonize the effects of full opioid agonists.
Reduces the doses of other drugs required for induction and maintenance of anaesthesia.
Monitoring
- Analgesic efficacy
- Respiratory status
- Cardiac status
Pharmacokinetics
Half-life
Absorption
Rapidly absorbed following IM injection (40-90% in humans). Sublingual bioavailability is ~55% in humans. Oral doses undergo a high first-pass effect in the GI mucosa and liver. In cats, oral transmucosal (buccal) absorption is comparable to IM or IV administration. In dogs, oral transmucosal absorption is about 50%. Subcutaneous administration may be less bioavailable.
Distribution
Highly bound (96%) to plasma proteins (not albumin). Concentrates in the liver, but also found in the brain, GI tract, and placenta. Crosses the placenta and is found in maternal milk at concentrations equal to or greater than plasma. Volume of distribution in cats is approximately 8 L/kg.
Metabolism
Metabolized in the liver by N-dealkylation and glucuronidation.
Elimination
Metabolites are eliminated by biliary excretion into the feces (≈70%) and urinary excretion (≈27%). Clearance in cats is about 20 mL/kg/min.
Overdose
Buprenorphine has a very high index of safety (ratio of lethal dose to effective dose is at least 1000:1 in rodents). Life-threatening acute overdoses are rare in veterinary medicine, but clinical signs are common.
- Clinical Signs (Dogs): Vocalization, ataxia, hypersalivation, hypothermia, and lethargy.
- Treatment: Supportive care. In cases of acute overdose causing severe respiratory or cardiac effects, naloxone and doxapram are suggested.
Note: Due to buprenorphine's extremely high affinity for the mu-receptor, standard doses of naloxone may be ineffective; very high doses of naloxone may be required to reverse respiratory depression.
Available products
Formulations
- Sublingual tablets
- Transdermal patch
- Sublingual film/tablet with naloxone
- Compounded sustained-release injection
Veterinary
- Compounded sustained-release injectable (SC) product (zoopharm.net)
Human-labeled
- Buprenorphine HCl for Injection: 0.324 mg/mL (equivalent to 0.3 mg/mL buprenorphine) (Buprenex)
- Buprenorphine HCl Sublingual Tablets: 2 mg & 8 mg (Subutex)
- Buprenorphine HCl Transdermal System (Butrans)
- Buprenorphine HCl Combinations (Sublingual Tablets): 2 mg buprenorphine/0.5 mg naloxone; 8 mg buprenorphine/2 mg naloxone (Suboxone)
Regulatory status
POM-V CD
POM-V CD SCHEDULE 3
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store at room temperature (15-30° C). Avoid temperatures above 40° C or below freezing. Store away from bright light. Autoclaving may considerably decrease drug potency. Stable between a pH of 3.5-5.
Client information
Buprenorphine is a potent pain reliever that is often sent home for use in cats and small dogs.
- Administration Technique: If you are instructed to give this medication by mouth, do not squirt it down the throat. Instead, place the tip of the syringe into the side of the mouth (the cheek pouch or under the tongue) and administer the liquid. The drug is absorbed directly through the gums. If swallowed, it is largely destroyed by the liver before it can work.
- Preparation: Pre-measuring dosages in syringes is highly recommended to ensure accurate dosing at home.
- What to Expect: Your pet may become slightly sleepy or, less commonly, a bit restless or vocal.
- Safety: This medication is very safe when used as directed, but it is a controlled substance. Keep it strictly out of reach of children and other pets.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.