Lactulose in the Treatment of Chronic Portal-Systemic Encephalopathy

Abstract

Abstract Current methods of controlling chronic portal-systemic encephalopathy (PSE) are unsatisfactory. Recently, lactulose treatment has been proposed. This synthetic disaccharide, which is neither absorbed nor hydrolyzed in the small bowel, is degraded by colonic bacteria, decreasing the pH of the colonic contents. In five of seven cirrhotic patients with PSE studied in a double-blind trial using sorbitol as control treatment, lactulose caused improvement that was associated with decreased stool pH and arterial ammonia levels and improvement in EEG. Sorbitol had no such effects. In seven patients long-term administration of lactulose was effective in preventing or ameliorating episodes of PSE despite discontinuing neomycin and doubling the daily protein intake. No consistent qualitative or quantitative alteration in stool flora was demonstrated. Improvement correlated with effective fecal acidification. Lactulose appears to exert its action by diminishing the absorption of ammonia from the acidified co...