Effect of lactulose on cerebral metabolism in patients with chronic portosystemic encephalopathy.

Cerebral blood flow and cerebral metabolism were studied in six patients with moderately severe portosystemic encephalopathy before and after a 10-day course of lactulose. As a result of therapy there was a mean increase in cerebral oxygen utilization but no changes in either mean glucose consumption or in mean cerebral blood flow. It appears therefore that the abnormalities in cerebral metabolism that have been previously described in patients with hepatic encephalopathy can be improved by the oral administration of lactulose.