Comparative acute effects of diflunisal and indomethacin on renal function in patients with cirrhosis and ascites.

Nonsteroidal anti-inflammatory drugs such as indomethacin induce a rapid reduction in renal perfusion and blunt the effects of diuretics in patients with cirrhosis and ascites. Nonacetylated salicylates reportedly cause less reduction in renal prostaglandins than do aspirin and other nonsteroidal anti-inflammatory drugs. To determine whether nonacetylated salicylates affect renal function, we compared diflunisal with indomethacin in nine patients with cirrhosis and ascites. One 50-mg dose of indomethacin reduced inulin clearance (91 +/- 11 to 76 +/- 11 ml/min) and blunted furosemide-stimulated natriuresis (58 +/- 12 to 36 +/- 9 mEq/h) and diuresis (1103 +/- 148 to 809 +/- 170 ml/h, all p less than 0.05). Three doses of diflunisal had no effect on inulin clearance (94 +/- 16 ml/min), natriuresis (60 +/- 12 ml/h), or diuresis (1041 +/- 112). Indomethacin caused greater reduction in urinary prostaglandin E2 (50% vs. 10%) and in serum thromboxane (94% vs. 80%) than diflunisal (p less than 0.05). Thus, nonacetylated salicylates avoid renal impairment and may be the preferred nonsteroidal anti-inflammatory drug in patients with cirrhosis and ascites.