Triamterene nephrolithiasis.

We identified triamterence in 181 renal calculi (o.4% of 50.000 calculi submitted for analysis). Triamterene formed the nucleus of the stone or was deposited with calcium oxalate or uric acid. One third of these stones were mainly or entirely triamterene, though a similar proportion had only minor amounts. A recommended dose of triamterene-hydrochlorothiazide sufficed to produce triamterene deposition in renal calculi. We estimate the annual incidence of the complication to be one per 1,500 users of triamterene-hydrochlorothiazide. Triamterene lithiasis develops particularly in persons who have had a renal stone, and they should not receive this drug.