Indapamide × Lithium

Indapamide is a thiazide-like diuretic. The lithium-raising mechanism is the same as hydrochlorothiazide: enhanced lithium reabsorption in the proximal tubules via subclinical volume depletion. Serum lithium rises.

Tremor, muscle twitching, nausea, diarrhoea, confusion, ataxia. Severe cases include seizures, coma, and nephrogenic diabetes insipidus with dehydration. Symptoms emerge when serum lithium exceeds 1.2 mmol/L.

Reduce lithium dose by 25–30% when starting indapamide; check serum lithium at 1 week, then monthly. Alternatives: amlodipine or a beta-blocker without lithium effects.