Acute effects of acetylsalicylic acid in patients with chronic renal insufficiency.

The effect of acetylsalicylic acid (ASA) in patients with renal insufficiency has been examined. In one investigation (A), in patients with a mean GFR of 23.0 ml/min the acute effects of ASA 750 mg i.v. (lysine-ASA 7.5 ml) and 0.9% NaCl 7.5 ml on renal water and solute output and on the clearance of inulin, creatinine and PAH were compared. In another (B) the effects of simultaneous administration of ASA 750 mg or 0.9% NaCl 7.5 ml i.v. with an infusion of furosemide 250 mg were investigated in six patients (mean GFR 12.9 ml/min) in a cross-over study. In study A there was a significant fall in urinary sodium excretion within the first 15 min after ASA administration, with a maximal decrease to 21% of the control period. Urine flow fell to 35%, osmolal clearance to 41%, inulin clearance to 54% and PAH clearance reabsorption of sodium increased. The effect of ASA lasted for 2-6 h. The mean salicylic acid concentration during the first two hours after ASA administration was 60.0 mug/ml, and the mean protein bound salicylic acid (SA) was 70.4%. There was no effect of placebo (0.9% NaCl 7.5 ml) on renal function. Pretreatment with ALA 750 mg i.v. attenuated the diuretic effect of furosemide 250 mg, and reduced creatinine clearance significantly within 0-2 h after drug administration.