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Pharmacology · Local anesthetics

Bupivacaine !

Long-acting amide local anaesthetic for epidurals, spinals and nerve blocks. It is the most cardiotoxic of its group.

Updated 2026-11-01

  • Class: Local anesthetics
  • Ion channel: Voltage-gated sodium channels (Nav)
  • ATC code: N01BB01
  • WHO Model List of Essential Medicines

Also called: Bupivacaine hydrochloride

The figure shows levobupivacaine (the S-enantiomer of bupivacaine) in the inner pore of the human Nav1.7 sodium channel.

Target in 3D: Voltage-gated sodium channels (Nav). PDB structure 8I5B (RCSB PDB, public domain). View the structure at RCSB PDB

Mechanism of action

Like other local anaesthetics, bupivacaine crosses the axon membrane in its un-ionised form and, once inside, blocks the pore of the voltage-gated sodium channel from the intracellular side. Without sodium current no action potential fires and pain does not reach the brain. It is highly lipid-soluble and protein-bound, so its effect lasts hours. In the heart it enters the sodium channel quickly and leaves very slowly in diastole, so the block builds up beat by beat.

  1. The un-ionised form crosses the axon membrane
  2. Inside, it blocks the sodium channel pore
  3. Without an action potential the pain signal does not travel
  4. Leaves the cardiac channel slowly: block builds up, risk of arrhythmia

Pharmacokinetics

Absorption
Slower than lidocaine from the injection site; a vasoconstrictor slows it further.
Distribution
Highly bound to plasma proteins; crosses the placenta.
Metabolism
Hepatic (CYP3A4) to pipecolylxylidine, which is then conjugated.
Elimination
Kidney, as metabolites.
Half-life
About 2.7 hours in adults; longer in liver failure.

Indications

  • Epidural anaesthesia and analgesia, including labour analgesia
  • Spinal anaesthesia (hyperbaric presentation)
  • Peripheral nerve and plexus blocks
  • Infiltration for prolonged postoperative analgesia

Adverse effects

Common

  • Hypotension and bradycardia
  • Nausea and vomiting
  • Chills
  • Drowsiness

Contraindications

  • Obstetric paracervical block (fetal bradycardia and death)
  • Intravenous regional anaesthesia (Bier block)
  • Hypersensitivity to amide-type local anaesthetics

Key interactions

Other local anaesthetics and class I antiarrhythmics
Additive toxicity.
Drugs that cause methaemoglobinaemia (nitrates, dapsone, sulfonamides)
Higher risk of methaemoglobinaemia.

What is monitored

  • Blood pressure, heart rate, ECG and saturation after injection
  • Level of consciousness and early signs of toxicity (metallic taste, tinnitus, agitation)
  • Level of sensory and motor block in epidurals

Administration and safety

  • Aspirate before every injection and give the dose in fractions; a negative aspiration does not rule out intravascular injection.
  • Have oxygen, resuscitation equipment and intravenous lipid emulsion at hand for systemic toxicity.
  • Presentations with and without epinephrine and a hyperbaric one for spinal use exist: check the label.
  • Multiple-dose vials with preservative are not used for epidural or caudal anaesthesia.

Nursing care

  • During and after the block: blood pressure, heart rate, saturation and consciousness at frequent intervals.
  • If there is numbness of the mouth, ringing in the ears, agitation or a seizure: stop the injection or infusion and call for help at once.
  • In labour epidurals: watch maternal blood pressure and fetal heart rate.
  • Protect the blocked limb and assess motor recovery before the patient gets up.

Pregnancy and breastfeeding

Widely used for labour and caesarean section by epidural or spinal route; it crosses the placenta and can cause fetal bradycardia, especially with paracervical block, which is contraindicated.

Test yourself

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

Why is bupivacaine more cardiotoxic than lidocaine?

It binds the cardiac sodium channel during systole and leaves very slowly in diastole, so the block builds up and causes ventricular arrhythmias and myocardial depression.

Which specific treatment is part of resuscitation from bupivacaine systemic toxicity?

Intravenous lipid emulsion, together with airway management, seizure control and cardiovascular support.

Which obstetric and regional techniques contraindicate bupivacaine?

Obstetric paracervical block and intravenous regional anaesthesia (Bier block).

Which early signs announce local anaesthetic systemic toxicity?

Perioral numbness, metallic taste, tinnitus, dizziness and agitation, before seizures and cardiovascular collapse.

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

Sources: DailyMed - BUPIVACAINE HYDROCHLORIDE injection, solution (DailyMed (U.S. National Library of Medicine), 2026); Goodman & Gilman's The Pharmacological Basis of Therapeutics, 14th ed., ch. 25 (McGraw Hill, 2023); eEML - Electronic Essential Medicines List (World Health Organization, 2025); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.