Clearance and micropuncture studies of the diuretic xipamide in dogs

Effects of the diuretic xipamide were examined by clearance and micropuncture techniques, and compared to clorothiazide. Xipamide decreased GFR and phosphate excretion. Reabsorption by superficial proximal tubules was unchanged. Since xipamide reduced single nephron filtration rate and GFR, a small effect on the proximal tubule may have been masked. Chlorothiazide decreased GFR but additionally decreased reabsorption by the proximal tubule. Xipamide was more chloruretic than natiuretic and probably inhibits reabsorption in the distal tubule.