Lidocaine Extraction Ratio Value — FRCA Primary MCQ

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HardPharmacology - General PrinciplesLidocaine Extraction Ratio ValueFRCA Primary

Lidocaine has a hepatic extraction ratio of approximately:

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Correct answer: B — 0.7

Lidocaine has an extraction ratio of ~0.7 making its clearance flow-dependent. Reduced hepatic blood flow (cardiac failure / beta-blockers / general anaesthesia) significantly decreases lidocaine clearance. Warfarin (~0.01) and phenytoin (~0.03) are low extraction drugs with capacity-dependent clearance.

Reference: Peck Hill Williams 2014 Pharmacology for Anaesthesia and Intensive Care