Bupivacaine Cardiotoxicity — MFDS Part 1 MCQ
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Correct answer: D — Bupivacaine
Bupivacaine has the lowest cardiovascular safety margin and greatest intrinsic cardiotoxic potential among the listed local anaesthetics. Its avid, slowly reversible binding to cardiac sodium channels allows conduction block to accumulate, predisposing to severe ventricular arrhythmias, myocardial depression and cardiac arrest. Bupivacaine-associated arrest may be resistant to defibrillation and require prolonged resuscitation. Lidocaine, articaine and mepivacaine can all cause local anaesthetic systemic toxicity, but their cardiac effects are generally less persistent than those of bupivacaine. Prilocaine is also less intrinsically cardiotoxic; its characteristic dose-related systemic toxicity is methaemoglobinaemia. Levobupivacaine and ropivacaine were developed as less cardiotoxic alternatives to racemic bupivacaine.
Reference: Neal JM et al. The Third American Society of Regional Anesthesia and Pain Medicine Practice Advisory on Local Anesthetic Systemic Toxicity: Executive Summary 2017, Table 3. Regional Anesthesia and Pain Medicine. 2018;43:113–123. https://www.medicines.org.uk/emc/product/13991/smpc