Effects of OKY 046, a thromboxane-synthase inhibitor, on renal function in nonazotemic cirrhotic patients with ascites.

To assess the possible role of increased renal thromboxane A2 (TXA2) synthesis in nonazotemic patients with cirrhosis and ascites and to establish the potential beneficial effect of inhibitors of renal TXA2 production in this clinical setting, we administered OKY 046, a selective TXA2 synthase inhibitor, 200 mg t.i.d. for 5 days, to 9 nonazotemic cirrhotic patients with ascites and avid sodium retention. OKY 046 inhibited platelet TXA2 production, as expressed by serum thromboxane B2 (TXB2) concentration, by approximately 85% (p less than 0.001 vs. baseline values) and reduced urinary TXB2 excretion by 72% (p less than 0.01). A significant increase of approximately 19% in inulin clearance was observed during the treatment (from 61.0 +/- 8.42 to 72.7 +/- 7.45 ml/min, p less than 0.05), whereas renal blood flow was unchanged (from 408.50 +/- 19.97 to 424.50 +/- 30.84 ml/min). Drug administration did not affect positive sodium balance [sodium excretion was 4.67 +/- 1.22 mEq/day before drug administration and 6.26 +/- 1.05 mEq/day during drug administration (on day 7)], plasma renin activity, plasma aldosterone concentration, or the urinary excretion of prostaglandin E2, 6-keto prostaglandin F1 alpha, or prostaglandin F2 alpha. These results suggest that renal TXA2 synthesis contributes to the regulation of renal hemodynamics in nonazotemic cirrhotic patients with ascites and avid sodium retention, but it does not seem to affect sodium balance.