Effect of lactitol on blood ammonia response to oral glutamine challenge in cirrhotic patients: Evidence for an effect of nonabsorbable disaccharides on small intestine ammonia generation

OBJECTIVE: Nonabsorbable disaccharides are widely used to decrease blood ammonia concentration. Their principal mode of action is the modification of pH and bacterial flora in the colon. The aim of the present study was to test the hypothesis that these drugs may also reduce small intestine ammonia generation. METHODS: Eight male cirrhotics without overt hepatic encephalopathy received 20 g of glutamine in 100 ml of water. Venous samples for whole blood ammonia were taken before, 30 and 60 min after the load. Immediately after the last blood sample the patients were submitted to the following psychometric tests: number connection test, Posner's attention test, and Sternberg paradigm. After the first glutamine load, patients were started on lactitol (initial dose 20 g, three times a day). Once two bowel movements/day were obtained and maintained for at least 5 days, oral glutamine challenge and psychometric tests were repeated. RESULTS: Ammonia increased significantly after the glutamin...