Local Anaesthetic Duration — MFDS Part 1 MCQ
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Correct answer: B — Bupivacaine
Bupivacaine is the long-acting amide local anaesthetic. Its extensive protein binding and high lipid solubility contribute to prolonged binding at neural tissues and a longer clinical effect. Dental comparative evidence also shows a longer anaesthetic effect with bupivacaine than with articaine, while articaine, lidocaine, prilocaine and mepivacaine are generally used as shorter- or intermediate-duration agents. Exact pulpal and soft-tissue anaesthesia times nevertheless vary with concentration, vasoconstrictor, dose, injection site and technique. Therefore, a claim such as a universal 12-hour inferior alveolar block would be too imprecise; the discriminating pharmacological classification is that bupivacaine is long-acting.
Reference: ADVANZ Pharma. Bupivacaine and Adrenaline (Epinephrine) Injection BP 0.25% w/v, 1 in 200,000, Summary of Product Characteristics, sections 4.1 and 4.8, updated July 2026. https://www.medicines.org.uk/emc/product/6622/smpc