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Thiopentone Concentration — FRCA Primary MCQ

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EasyPharmacology - Intravenous AnaestheticsThiopentone ConcentrationFRCA Primary

Thiopentone is prepared as a 2.5% solution. How many mg are in each mL?

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

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Correct answer: B — 25 mg/mL

A 2.5% solution = 2.5 g per 100 mL = 2500 mg per 100 mL = 25 mg/mL. Thiopentone 500 mg is dissolved in 20 mL water for injection to give a 2.5% solution at pH 10.8.

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