['Losartan, a highly selective angiotensin II type 1 receptor antagonist, has been reported to have a significant portal hypotensive effect in cirrhotic patients. A recent study also showed that losartan exerted a dramatic natriuretic effect in preascitic cirrhosis. The influence of losartan on renal hemodynamics and sodium homeostasis in cirrhotic patients with ascites is unclear. This study was undertaken to evaluate the renal effects of 1-week losartan treatment in cirrhotic patients with and without ascites.', 'All 12 patients in the study received a daily oral dose of 25 mg losartan for 7 consecutive days. Effective renal plasma flow, urine volume, creatinine clearance, 24h urine sodium excretion and fractional excretion of sodium, blood urea nitrogen, and serum creatinine were measured before and after treatment.', 'In cirrhotic patients without ascites, creatinine clearance, 24-h urinary sodium excretion, and fractional excretion of sodium were significantly increased after losartan administration. Effective renal plasma flow and serum creatinine showed almost no change after treatment. In cirrhotic patients with ascites, creatinine clearance, 24-h urinary sodium excretion, fractional excretion of sodium, and effective renal plasma flow were significantly increased after losartan administration. In addition, the magnitudes of the increases in the fractional excretion of sodium and in the 24-h urinary sodium excretion were greater in cirrhotic patients with ascites than in those without ascites.'] Does one-week losartan administration increase sodium excretion in cirrhotic patients with and without ascites?