Studies with triamterene derivatives for oral application.

The diuretic effects, expressed as the urinary Na+/K+ ratios, after oral application of triamterene (TA) and three representatives of a series of TA derivatives - dimethylaminohydroxypropoxytriamterene, carboxybutoxytriamterene and its ethyl ester - are investigated in male Wistar rats. Although the TA analogues are potent diuretics when they are given intravenously, very high oral doses are necessary to produce slight diuretic effects. This result is due to an insufficient absorption of the compounds in the gastrointestinal tract of the rat.