Effect of prolonged thiazide treatment on renal lithium clearance.

Renal lithium clearances were determined after the administration of a small test dose of lithium carbonate in 22 patients when they were on long-term treatment with thiazides and when they were not on such treatment. Thiazide administration led to a 24% reduction in the lithium clearance. Diuretic drugs should be used with caution in patients given lithium treatment, and lithium should be used with caution in patients receiving diuretic treatment.