Profound fatigue is a clinically significant complication of chronic liver disease. A mechanism of fatigue in experimental animals and male athletes appears to be increased serotoninergic neurotransmission in the brain. Recently, attempts have been made to assess the efficacy of a serotonin antagonist, specifically the 5-HT3 receptor subtype antagonist, ondansetron, in ameliorating fatigue in patients with chronic liver disease.

However, the results of a randomized controlled trial of ondansetron for fatigue in patients with primary biliary cirrhosis did not indicate that ondansetron was either effective or ineffective. The reasons for the uncertain outcome of the randomized controlled trial are not clear. One contributing factor may have been the use of subjective indices of fatigue as primary efficacy endpoints. There is a need to develop objective quantitative primary efficacy endpoints for use in trials of therapy for fatigue.

Another contributing factor may relate to the conduct of a randomized controlled trial not invariably being the optimal approach to resolve a specific clinical issue, particularly when the application of statistical methods yields equivocal findings. When the results of a randomized controlled trial are indecisive, findings based on clinical judgement, medicine's most important asset, should be carefully evaluated.