Nephrotic changes in the rat induced by overdosage of triamterene

Daily treatment of rats with 2,4,7-triamino-6-phenylpteridine (triamterene, Dyrenium) a potassium sparing diuretic, in daly doses of 1.5 mg, 3 mg and 4.5 mg/100 g body weight over the period of three weeks caused severe degenerative changes of renal cortical and medullary tubules resembling osmotic (sucrose) nephrosis. The undesirable side-effects were absent in the kidneys of intact rats receiving human therapeutic dose of triamterene (0.36 mg/100 g body weight) and even higher dose (1.5 mg/100 g body weight) but administered according to the prescription of treatment recommended by the manufacturer--daily over the first week and three times weekly after that. Rats .2 days after adrenalectomy administered triamterene in daily dose of 1.5 mg/100 g body weight, survived no more than 6--7 days of treatment. The results presented in this paper undoubtedly show that triamterene, although a mild diuretic agent, should be monitored in order to avoid undesirable side-effects. In addition care should be taken in patients with hypofunction of adrenal cortex.