LA + opioid epidural admixture Pregnancy: Bupivacaine crosses the placenta to a lesser degree than lidocaine or mepivacaine (foetal:maternal ratio 0.2-0.4), and its greater protein binding limits the amount available to cross the placenta. Regular use during pregnancy may cause drug dependence in the foetus, leading to withdrawal symptoms in the neonate — if opioid use is required for a prolonged period, advise the patient of the risk of neonatal opioid withdrawal syndrome and ensure appropriate treatment will be available. Administration during labour may depress respiration in the neonate and an antidote for the child should be readily available. Breast-feeding: at recommended doses bupivacaine enters breast milk in quantities too small to affect the child, but administration to nursing women is not recommended as fentanyl may be secreted in breast milk and may cause respiratory depression in the infant.

Bupivacaine with fentanyl

Brand names: various — epidural pre-mix

A combination of the long-acting amide local anaesthetic bupivacaine with the opioid fentanyl, used principally for epidural and intrathecal analgesia, including labour and postoperative pain.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: Continuous epidural infusion of bupivacaine 1 mg/mL with fentanyl 2 micrograms/mL. Analgesia in labour (lumbar epidural): 10-15 mL/hour, delivering bupivacaine 10-15 mg/hour and fentanyl 20-30 micrograms/hour. Control of post-operative pain (thoracic, upper or lower abdominal epidural): 4-15 mL/hour, delivering bupivacaine 4-15 mg/hour and fentanyl 8-30 micrograms/hour

Route: Epidural use only, by continuous infusion via an infusion pump. This formulation is not to be used as a bolus. The infusion line should be clearly marked to avoid confusion with intravenous lines and adequate filtering should be an integral part of the line

Frequency: Continuous infusion; the length of continuous post-operative epidural infusions should be minimised because of the increased risks of reaching a toxic plasma concentration, inducing local neural injury or local infection. Administration has not been adequately studied for more than 72 hours

Max: It should not be necessary to exceed an infusion dosage of 20 mg/hour for bupivacaine. The maximum accumulated dosage should not exceed 400 mg of bupivacaine and 720 micrograms of fentanyl for a 24 hour period in a 70 kg adult

Source: eMC SPC for Bufyl 1 mg/ml, 2 microgram/ml Solution for infusion (bupivacaine with fentanyl fixed combination). Dosing should be titrated to individual patient requirements and the lowest dose required to provide adequate analgesia should be used; consult standard textbooks for factors affecting specific block techniques. When calculating the dose for post-operative analgesia, take into account the intra-operative use of bupivacaine and/or fentanyl (or other opioid agonist analgesic). Careful aspiration before starting the infusion is recommended to prevent intravascular injection, and the infusion rate should be slow with continual assessment of the patient. Monitoring: continuous review after starting the infusion, including periodic blood pressure/pulse measurement and assessment of pain and sedation at a minimum of 30-minute intervals; maintain verbal contact where the patient is conscious; segmental testing of the level of the block at least hourly throughout the infusion, with appropriate monitoring to detect progressive spread or increasing density of block; periodic assessment of motor block using the Bromage score. For obstetric analgesia the test level T5/T6 should be clearly marked; for post-operative analgesia the level of block should be determined relative to the site of surgery. Routine maternal cardiovascular and foetal monitoring should be performed — in labour, foetal heart rate should be monitored every 5 minutes for 30 minutes and then as appropriate. Consider using a different brand of proprietary pump from that used for intravenous infusions; the pump should allow accurate infusion rates down to 1 mL/hour, have positive pressure drive (not gravity feed), a back-up battery and an automatic infusion shut-off if power is lost or the front of the pump is accidentally opened. Should only be used by or under the supervision of clinicians experienced in regional anaesthesia. Before starting treatment with opioids, discuss and put in place a strategy for ending fentanyl treatment to minimise the risk of addiction and drug withdrawal syndrome. Elderly and debilitated patients, including those with advanced liver disease or severe renal dysfunction, should be given a reduced dosage commensurate with their physical condition. PAEDIATRIC: the use of bupivacaine with fentanyl in children is not recommended since experience in paediatric patients is limited. §4.5 (interactions) was not included in this bundle and the fentanyl adverse-reaction table in §4.8 is cut off at the source-fetch limit.

Dose adjustments

Renal

Since bupivacaine and fentanyl are metabolised in the liver and excreted via the kidneys, the possibility of medicine accumulation should be considered in patients with hepatic and/or renal impairment, with a possible reduction in dosage depending on the severity of their impairment. Debilitated or elderly patients, including those with advanced liver disease or severe renal dysfunction, should be given a reduced dosage commensurate with their physical condition.

Dose auto-extracted from UK Summary of Product Characteristics (SPC) via the eMC; US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Hypersensitivity to the active substances or to any of the excipients
Acute respiratory depression; fentanyl should not be used in patients with or susceptible to respiratory depression, such as comatose patients who may have head injuries or a brain tumour
Acute alcoholism
Raised intracranial pressure or head injury — fentanyl may obscure the clinical course of patients with head injury
Hypovolaemia and complete heart block
Intravenous regional anaesthesia (Bier's block), as unintentional passage of local anaesthetic into the systemic circulation despite a tourniquet may cause systemic toxic reactions
Obstetrical paracervical block anaesthesia
Concurrent administration of monoamine oxidase inhibitors, or within 2 weeks of their discontinuation
Contraindications of epidural anaesthesia itself: active disease of the central nervous system (meningitis, poliomyelitis, intracranial haemorrhage, subacute combined degeneration of the cord due to pernicious anaemia, spina bifida or meningomyelocele, cerebral or spinal tumours); tuberculosis of the spine; inflammation and/or pyogenic infection of the skin at or adjacent to the site of lumbar puncture; a diagnosed arteriovenous malformation in the vertebral column close to the proposed puncture site; cardiogenic shock; coagulation disorders or ongoing anticoagulant therapy; an expanding cerebral lesion, tumour, cyst or abscess

Side effects

Hypotension and nausea (very common)
Bradycardia, vomiting, urinary retention, nervousness, paraesthesia, dizziness and hypertension (common)
Signs and symptoms of CNS toxicity — euphoria, disorientation, convulsions, circumoral paraesthesia, numbness of the tongue, hyperacusis, visual disturbances, loss of consciousness, tremor, light-headedness, tinnitus, pruritus, diaphoresis, dysarthria, muscle twitching (uncommon)
Cardiovascular collapse or cardiac arrest, cardiac arrhythmias; laryngospasm, respiratory depression or respiratory arrest; allergic reactions, bronchospasm, anaphylactic reaction/shock (rare)
Weakness, persistent anaesthesia, loss of sphincter control, neuropathy, peripheral nerve injury, arachnoiditis, paresis and paraplegia; diplopia, miosis (rare). Inadvertent subarachnoid injection may lead to cardiovascular collapse, unconsciousness and respiratory arrest; accidental intrathecal injection may be recognised by early signs of spinal block such as hypotension, bradycardia and difficulty in breathing

Interactions

Monoamine oxidase inhibitors — concurrent administration, or administration within 2 weeks of their discontinuation, is contraindicated (SPC §4.3; §4.5 was not retrieved in this bundle, so the full interaction profile has not been extracted)

Clinical monograph

How it works

Bupivacaine blocks neuronal sodium channels to produce a sensory and motor block, while fentanyl, an opioid agonist acting on spinal opioid receptors in the dorsal horn, provides synergistic analgesia allowing a lower local-anaesthetic concentration.

Prescribing in practice

The fentanyl component can cause delayed respiratory depression after neuraxial administration, so monitor respiration and sedation and have naloxone and resuscitation facilities available.
Bupivacaine remains cardiotoxic if injected intravascularly, so correct catheter placement and aspiration are essential before dosing.
Neuraxial opioids may also cause pruritus, urinary retention and nausea; use only where appropriate monitoring is in place.

Monitoring

Monitor respiratory rate, sedation level, blood pressure and block height regularly throughout neuraxial infusion.

Counselling the patient

Team: observe for delayed respiratory depression and excessive sedation after neuraxial opioid use.
Patient: report itching, difficulty passing urine, drowsiness or difficulty breathing.

Evidence & guidelines

Combining low-dose local anaesthetic with a neuraxial opioid for synergistic epidural analgesia is well-established obstetric and perioperative practice.

Reference: OAA / RCOA / AAGBI guidelines; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways