When does diuretic start showing its effect after taking tablet?

Diuretics: Generally speaking people with healthy guts would start seeing increased urine output in about 90-120 minutes. However with cirrhosis, portal hypertension, and possibly ascites (water in the abdomen), the oral medications may not be absorbed well since the intestinal and stomach lining may be boggy with water in which case you might need an intravenous diuretic.