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Lithium toxicity monitoring — GPhC CRA MCQ

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HardCNS TherapeuticsLithium toxicity monitoringGPhC CRA

A patient taking lithium and bendroflumethiazide has 36 hours of vomiting and diarrhoea, tremor and unsteady gait. What is the immediate investigation plan?

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Correct answer: EUrgent lithium level, renal function and electrolyte assessment

Dehydration reduces lithium clearance and thiazides can further raise its concentration. Tremor and ataxia suggest toxicity, so lithium should be withheld pending urgent clinical assessment, a correctly interpreted concentration, renal function and electrolytes.

Reference: BNF: lithium carbonate: https://bnf.nice.org.uk/drugs/lithium-carbonate/