Edrophonium Short Duration — FRCA Primary MCQ
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Correct answer: D — Binds reversibly to the anionic site only giving a shorter duration of action
Edrophonium binds reversibly to the anionic site of AChE via electrostatic and hydrogen bonding (not carbamylation). This gives it a rapid onset (30-60 seconds) but very short duration (~10 minutes). Neostigmine carbamylates the esteratic site giving a longer duration (60-90 minutes). Edrophonium is used for the Tensilon test in myasthenia gravis diagnosis.
Reference: Peck Hill Williams 2014 Pharmacology for Anaesthesia and Intensive Care