NEW YORK (Reuters Health) – Rifaximin improves driving simulator performance in patients with cirrhosis and minimal hepatic encephalopathy, researchers report in the February issue of Gastroenterology.

“The study findings with rifaximin,” Dr. Jasmohan S. Bajaj told Reuters Health by email, “are very encouraging because they show that cognitive deficits can be turned back and can also translate into driving skill improvement.”

“However,” he added, “driving simulation was used in this trial, therefore, further research is needed to evaluate whether rifaximin can improve real driving outcomes.”

Dr. Bajaj of Virginia Commonwealth University, Richmond and colleagues note that such patients have cognitive dysfunction that can lead to difficulties in driving. They are at increased risk of driving offenses and have poor insight into their driving skills.

There is evidence that agents including rifaximin can improve cognition, but it’s not known whether driving skills also improve.

To investigate, the team randomized 42 patients who were current drivers to rifaximin 550 mg twice daily or to placebo.

Over the 8-week study period, patients given rifaximin made significantly greater improvements in avoiding total driving errors (76% versus 31%). This was also true of speeding (81% versus 33%) and of making illegal turns (62% versus 19%). Collisions were not significantly affected.

In addition, cognitive performance improved in 91% of the active treatment group compared to 61% of the placebo patients. There was a significant improvement in the psychosocial aspect of the Sickness Impact Profile in the rifaximin group, but no other changes were observed.

The only serum marker alteration seen was a significant increase in the anti-inflammatory cytokine interleukin-10 in the rifaximin group.

This trial, the researchers conclude “provides a proof-of-concept that improvement in clinically relevant outcomes such as driving performance can be observed with therapy for minimal hepatic encephalopathy using rifaximin.”

Gastroenterology 2011;140:478