Concomitant loop diuretics and ACE inhibitors increase risk of lithium toxicity in elderly people.

MAIN RESULTS Over 10 years, 413 people (4%) receiving continuous treatment with lithium were admitted into hospital at least once for lithium toxicity. Of these, 15% required critical care, 3% dialysis, and 5% died before discharge. Existing use of loop diuretics and ACE inhibitors was associated with a modestly increased risk of lithium toxicity. Initiating loop diuretics or ACE inhibitors significantly increased the risk of lithium toxicity: within one month of starting treatment. Hospitalisation was almost six times more likely for people initiating loop diuretics, and four times more likely for those initiating ACE inhibitors compared with case controls (see table). Thiazide diuretics and NSAIDs were not associated with an increased risk of lithium toxicity in both new and existing users. CONCLUSIONS Loop diuretics and ACE inhibitors taken concomitantly with lithium significantly increase the risk of lithium toxicity within one month of beginning treatment.