Treatment of cirrhotic hepatic encephalopathy with L-dopa. A controlled trial.

It has been suggested that hepatic encephalopathy could be due to the accumulation of false neurotransmitters and that the administration of a neurotransmitter precursor such as L-dopa would be beneficial to cirrhotic patients with hepatic encephalopathy. A prospective randomized controlled study was carried out to determine whether L-dopa has any effect on the course of cirrhotic hepatic encephalopathy. L-Dopa, L-Dopa and dopa-decarboxylase inhibitor, or placebo was given orally for 7 days to 75 cirrhotic patients with hepatic encephalopathy. The effect was assessed by clinical parameters as well as serial electroencephalograms. There was no statistically significant difference with respect to clinical improvement or deterioration in patients treated with either L-dopa or L-dopa and dopa-decarboxylase inhibitor or placebo. It is concluded that L-dopa is ineffective in the treatment of cirrhotic hepatic encephalopathy. Inefficacy was not due to late onset of treatment, to poor intestinal absorption of L-dopa, to destruction of L-dopa in the blood, or to impaired passage of L-dopa into the cerebrospinal fluid.