1. The effects of oral sulindac, 600 mg daily, on renal function and plasma hormones were studied in eight subjects with chronic renal failure.
2. Renal function and plasma hormones were measured before drug administration and then after taking sulindac for 28 days.
3. Effective renal plasma flow was reduced in all subjects after 28 days but the glomerular filtration rate did not change.
4. Plasma renin activity, potassium and aldosterone concentrations and urinary sodium excretion did not change but urinary prostaglandin E2 excretion fell significantly.
5. Sulindac may be a relatively renal-sparing drug in its effects on the hormonal control of glomerular function.