skip to main content

Ester Local Anaesthetic — FRCA Primary MCQ

Instant feedback + full explanation. One question, done properly.

EasyPharmacology - AnalgesicsEster Local AnaestheticFRCA Primary

Which of the following local anaesthetics is an ester?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: DChloroprocaine

Chloroprocaine is an ester local anaesthetic. Its intermediate linkage is an ester bond, which is rapidly hydrolysed in plasma by plasma cholinesterase (pseudocholinesterase); this contributes to its short duration of action. Bupivacaine, ropivacaine, prilocaine and lidocaine all contain an amide linkage and are therefore amide local anaesthetics. Amide agents predominantly undergo enzymatic metabolism in the liver, although the precise metabolic pathways and importance of extrahepatic metabolism vary between drugs. Classification should ultimately be based on the chemical linkage rather than solely on a naming mnemonic, because such mnemonics are useful examination aids but are not universally reliable.

Reference: Electronic Medicines Compendium. Ampres 10 mg/ml solution for injection, Summary of Product Characteristics, section 5.1 Pharmacodynamic properties; updated 26 October 2023. https://www.medicines.org.uk/emc/product/15158/smpc