Further studies on the natriuretic activity of p-hydroxytriamterene.

p-Hydroxytriamterene, the phase I metabolite of triamterene, increased sodium excretion without affecting urinary volume or potassium when administered orally to rats on sodium deficient diets at doses of 15 and 30 mg/kg. The urine of these animals also contained p-hydroxytriamterene sulfuric acid ester, the phase II metabolite of triamterene but did not contain p-hydroxytriamterene. This evidence indicates that p-hydroxytriamterene is orally active as a potassium-sparing natriuretic in rats.