Buprenorphine

Background

• Partial mu-opioid agonist and kappa-opioid antagonist used for opioid use disorder and chronic pain
• Has a ceiling effect for respiratory depression — at higher doses, respiratory depression plateaus, making it significantly safer than full agonists in overdose
• ED-initiated buprenorphine increases 30-day treatment engagement ~5-fold compared to referral alone (D'Onofrio 2015 RCT)
• Combined with naloxone in most sublingual/buccal formulations (Suboxone) to deter IV misuse — naloxone has no clinical effect when taken sublingually as intended
• No special waiver or certification is required to prescribe buprenorphine — the X-waiver (DATA 2000) was permanently eliminated by the Consolidated Appropriations Act of 2023

Administration

• Type: Opioid — partial mu-agonist; used for OUD maintenance/induction and chronic pain
• Dosage Forms:
  • Sublingual tablet: buprenorphine/naloxone 2 mg/0.5 mg, 4 mg/1 mg (generic), 8 mg/2 mg, 12 mg/3 mg; buprenorphine monoproduct 2 mg, 8 mg
  • Sublingual/buccal film: buprenorphine/naloxone 2 mg/0.5 mg, 4 mg/1 mg, 8 mg/2 mg, 12 mg/3 mg (Suboxone); buprenorphine buccal film 75, 150, 300, 450, 600, 750, 900 mcg (Belbuca — for pain)
  • Extended-release subcutaneous injection: Sublocade 100 mg, 300 mg (monthly); Brixadi 8, 16, 24, 32 mg (weekly) and 64, 96, 128 mg (monthly)
  • Transdermal patch: 5, 7.5, 10, 15, 20 mcg/hr (Butrans — for pain)
  • Injectable solution: 0.3 mg/mL (Buprenex — for acute pain, available IV/IM)
• Routes of Administration: sublingual, buccal, subcutaneous, transdermal, IV, IM
• Common Trade Names: Suboxone (buprenorphine/naloxone), Subutex (buprenorphine mono), Sublocade (extended-release monthly), Brixadi (extended-release weekly/monthly), Belbuca (buccal film for pain), Butrans (transdermal patch for pain), Buprenex (injectable)

Adult Dosing

ED-Initiated Buprenorphine

There are three induction strategies. Choice depends on withdrawal status and clinical scenario.

Traditional Induction (patient in moderate-severe withdrawal, COWS ≥8-12)

• For Clinical Opioid Withdrawal Scale (COWS) ≥8: give 4 to 8mg of Buprenorphine, observe 30 to 45min
  • Redose if COWS remains ≥8. Then discharge home with 16 mg a day to bridge until follow-up (an X-waiver is no longer required to prescribe buprenorphine).
• For Clinical Opioid Withdrawal Scale (COWS) 0-7: Consider observing the patient until their COWS score is >8 for the standard buprenorphine induction.
  • Alternatively, you can prescribe consider unobserved home induction instructions available on paper and app .

• If sublingual tablets/films unavailable then intravenous/intramuscular formulation (dose 0.3-0.9 mg every 6-12 hours) has been used for opioid withdrawal in the ED and hospitalized patients.

NIH National Institute on Drug Abuse ED Buprenorphine algorithm

High-Dose ("Macro") Induction

• For patients in moderate-severe withdrawal, especially those using fentanyl/high-potency synthetic opioids
• Day 1: Buprenorphine/naloxone 8 mg SL; may repeat 8 mg in 1-2 hours (total up to 16-32 mg on day 1)
• Buprenorphine has been shown to be safe at doses up to 32-64 mg without respiratory depression
• If precipitated withdrawal occurs with the initial dose, give more buprenorphine (not less) to saturate remaining unoccupied receptors
• Discharge dose: 16 mg/day (or the total daily dose that stabilized the patient in the ED), prescribed as buprenorphine/naloxone with outpatient follow-up

Low-Dose ("Micro") Induction

• For patients not yet in withdrawal or who cannot tolerate withdrawal (e.g., patients on full-agonist opioids, patients using fentanyl who cannot wait for COWS ≥8)
• Start with very low doses of buprenorphine (e.g., 0.5-1 mg SL) and gradually increase over 3-7 days while the full agonist is slowly tapered
• Avoids precipitated withdrawal by allowing gradual receptor binding
• Typically not completed in a single ED visit — requires either observation unit admission or close outpatient follow-up

Precipitated Withdrawal Management

• Occurs when buprenorphine is given while a full agonist is still occupying mu receptors (more common with fentanyl due to lipophilicity and depot effect)
• Treat with more buprenorphine — increasing the dose is first-line to overcome competition for receptor binding
• Adjunctive symptom management:
  • Ondansetron for nausea/vomiting
  • Loperamide for diarrhea
  • Clonidine 0.1-0.2 mg for autonomic symptoms
  • NSAIDs or acetaminophen for myalgias
  • IV fluids for dehydration

Acute Pain (non-OUD)

• IV/IM: 0.3 mg q6-8h PRN (parenteral formulation)
• Transdermal (Butrans): 5-20 mcg/hr patch, changed weekly
• Buccal film (Belbuca): Starting dose 75 mcg q12h, titrate as needed

Pediatric Dosing

• OUD: Generally managed by addiction medicine/pediatric specialists; weight-based dosing for adolescents ≥16 years follows adult guidelines
• Acute pain (parenteral): 2-12 years: 2-6 mcg/kg q4-6h PRN

Special Populations

Pregnancy

• Buprenorphine is recommended in pregnancy for OUD — associated with reduced neonatal abstinence syndrome (NAS) severity and shorter NICU stays compared to methadone
• Use buprenorphine monoproduct (without naloxone) in pregnancy — although buprenorphine/naloxone is increasingly accepted and may be used if the monoproduct is unavailable
• Do NOT stop buprenorphine in pregnancy — withdrawal poses greater risk to fetus than continued treatment

Lactation

• Buprenorphine is considered compatible with breastfeeding — minimal transfer to breast milk, low oral bioavailability in the infant
• Benefits of breastfeeding generally outweigh risks in stable patients on buprenorphine maintenance
• Monitor infant for sedation and adequate weight gain

Renal Dosing

• No dose adjustment required (primarily hepatically metabolized)

Hepatic Dosing

• Use with caution in moderate hepatic impairment; reduce dose
• Avoid or do not use in severe hepatic impairment
• Extended-release formulations (Sublocade, Brixadi) are contraindicated in moderate-severe hepatic impairment (cannot rapidly adjust dose once injected)
• Obtain LFTs if clinical concern, but LFTs are not required before initiating buprenorphine in the ED

Contraindications

• Allergy to buprenorphine or naloxone
• Severe respiratory depression (current; note: ceiling effect makes this very rare with buprenorphine alone)
• Severe hepatic impairment (for extended-release formulations)
• Not contraindicated in patients on benzodiazepines — co-prescribing carries risk but withholding buprenorphine carries greater mortality risk from untreated OUD

Drug Interactions

• Benzodiazepines and other CNS depressants: Additive respiratory depression risk, but this is NOT a contraindication to buprenorphine initiation — the risk of death from untreated OUD exceeds the risk of co-prescribing
• CYP3A4 inhibitors (ketoconazole, ritonavir, erythromycin): May increase buprenorphine levels — monitor for sedation
• CYP3A4 inducers (rifampin, carbamazepine, phenytoin): May decrease buprenorphine levels — may require dose increase
• Full mu-agonist opioids: Buprenorphine may precipitate withdrawal if given while full agonist is occupying receptors; full agonists may have diminished effect in patients on buprenorphine maintenance
• Naloxone: Higher doses of naloxone (standard overdose doses) may precipitate withdrawal in buprenorphine-dependent patients, though buprenorphine's high receptor affinity makes it relatively naloxone-resistant

Adverse Reactions

Serious

• Respiratory depression (rare due to ceiling effect; risk increased with concurrent CNS depressants or IV misuse)
• Precipitated opioid withdrawal (if given before full agonist has cleared)
• Hepatotoxicity (elevated transaminases; more common with pre-existing hepatic disease or hepatitis)
• QT prolongation (mild; less clinically significant than with methadone)
• Adrenal insufficiency (rare, with chronic use)
• Neonatal withdrawal syndrome (in infants born to mothers on buprenorphine)
• Anaphylaxis/angioedema (rare)

Common

• Constipation
• Nausea, vomiting
• Headache
• Insomnia
• Diaphoresis
• Peripheral edema
• Dizziness, somnolence
• Oral hypoesthesia (sublingual/buccal formulations)
• Injection site reactions (extended-release formulations)

Pharmacology

• Half-life: 24-42 hours (sublingual); 43-60 days (Sublocade depot)
• Metabolism: Hepatic via CYP3A4 to active metabolite norbuprenorphine; also undergoes glucuronidation
• Excretion: Primarily fecal (~70%); renal (~30% as metabolites)
• Protein binding: ~96%
• Ceiling effect for respiratory depression occurs at approximately 16-32 mg sublingual

Mechanism of Action

• Partial mu-opioid receptor agonist: Produces submaximal activation — provides analgesia and prevents withdrawal but with limited euphoria and a ceiling effect on respiratory depression
• Kappa-opioid receptor antagonist: May contribute to antidepressant and anti-dysphoric effects
• Very high receptor binding affinity: Displaces full agonists from mu receptors (causes precipitated withdrawal if administered too early) and blocks effects of subsequently administered full agonists

Comments

• ED-initiated buprenorphine is the standard of care — supported by ACEP policy statement, ASAM guidelines, and landmark RCT data showing reduced opioid use, increased treatment engagement, and reduced mortality
• Prescribe a bridge supply at discharge: At minimum, prescribe enough buprenorphine/naloxone to last until the outpatient follow-up appointment (typically 7-14 day supply). A common discharge dose is 16 mg/day
• Buprenorphine and buprenorphine/naloxone are clinically interchangeable. Buprenorphine/naloxone is now generic in the US
• Patients presenting on extended-release buprenorphine (Sublocade, Brixadi) who have breakthrough withdrawal may need supplemental sublingual buprenorphine — consult with the patient's prescriber
• For patients with OUD in the ED who decline buprenorphine, still treat withdrawal symptoms, provide harm reduction resources (naloxone kit, fentanyl test strips), and offer a prescription or referral for a future visit

Indications by Condition

The following table is automatically generated from disease/condition pages across WikEM.

Indication	Dose	Context	Route	Population
Neonatal abstinence syndrome	5mcg/kg q8hr initially (max 20mcg/kg q8hr)	Alternative to morphine; may reduce hospital stay	Sublingual	Pediatric
Opioid toxicity	4 mg SL initial; may give additional 4 mg SL after 1-2 hours (total 8-16 mg on day 1)	ED-initiated buprenorphine for OUD	SL	Adult

See Also

• Opioid use disorder
• Opioid withdrawal
• Opioid overdose
• Naloxone
• Methadone