A patient receiving a bupivacaine epidural develops cardiovascular collapse with a wide-complex arrhythmia refractory to standard ACLS measures. The specific antidote is:

• A IV sodium bicarbonate to alkalinise plasma
• B IV magnesium sulphate for torsades
• C IV atropine for vagal bradycardia
• D IV lipid emulsion (Intralipid) therapy ✓

Explanation

Bupivacaine cardiotoxicity is particularly severe because it binds cardiac sodium channels with high affinity and very slow off-kinetics (tonic block), causing refractory ventricular arrhythmias and electromechanical dissociation. The specific treatment is intravenous lipid emulsion therapy (e.g., 20% Intralipid), which is believed to act as a lipid 'sink' sequestering bupivacaine away from cardiac tissue, in addition to possible direct metabolic effects on cardiac mitochondria. Sodium bicarbonate helps for lignocaine overdose, not bupivacaine.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.