Background: Recently, the serotonin antagonist ondansetron has been reported to have a positive effect on cholestasis-associated pruritus.
Objectives: To study the effect of orally administered ondansetron on pruritus in chronic liver disease in a randomized, placebo-controlled, double-blind, cross-over study.
Methods: Subjective severity of pruritus was assessed using a visual analogue scale (VAS) recorded four times daily by the patients. After a one week pretreatment baseline period the patients were randomized to receive ondansetron tablets 8 mg tds or placebo tablets tds for one week. Following a one week wash-out period patients were switched to the other treatment for one week. The study was ended by an additional follow-up week without medication. For each day peak VAS values were determined and the mean value of the last five days of each week was calculated and referred to as the composite peak VAS score.
Results: We observed a significant but moderate reduction of the composite peak VAS score of 1.34 points (CI(95%): 0.12-2.56; P=0.033) during treatment with ondansetron as compared to placebo (treatment effect). In addition, a period effect was observed: a reduction of composite peak VAS score by 1.26 points (C1(95%): 0.04-2.48; P=0.044) was seen in the second treatment period as compared to the first period, irrespective of the kind of treatment. Although under treatment with ondansetron a significant improvement of itching as assessed by the VAS score was demonstrated, this treatment was not preferred over placebo by the patients.
Conclusions: The 5-hydroxytryptamine receptor type 3 antagonist ondansetron has a small, but significant positive effect on pruritus in chronic liver disease as compared to placebo.