The findings of this review indicate that the number of systemic and topical drugs used for the different subforms of pruritus is increasing. Different interventions have been shown to be effective in the treatment of pruritus of different origins. Nevertheless, an optimal therapy for pruritus is constrained due to the limited understanding of crucial itch mediators and receptors in the various subforms of itch. Ideal antipruritic therapies are still lacking, especially for palliative care patients.
This systematic review also indicates that there is insufficient evidence to give any concrete recommendations regarding treatment of pruritus in palliative care patients. Due to the very small sample sizes and poor methodological quality of the majority of studies that were included, the results of this review need to be interpreted with caution. Furthermore, the generalizability is questionable. Additional studies, and particularly carefully designed treatment trials, are needed to provide valid evidence for adequate treatment of pruritus in palliative care patients.
A randomized, placebo-controlled, double-blind trial of ondansetron in renal itch.
Renal itch is a relatively common and distressing problem for patients with chronic renal failure. Ondansetron, a serotonin type 3 receptor antagonist was developed for relief of chemotherapy induced nausea. Recently, anecdotal reports describe relief of renal itch with ondansetron.
                We performed a double-blind randomized placebo-controlled trial to objectively assess the effectiveness of ondansetron in renal itch.
                With approval from the local ethical committee, 24 patients on haemodialysis were enrolled in the trial. On a random basis 14 patients were blindly allocated to the ondansetron-placebo sequence and 10 to the placebo-ondansetron sequence. Baseline values for itch were obtained for 7 days before the treatment period and there was a 7-day washout between the treatment periods. During the treatment patients received either 8 mg of ondansetron three times a day or a placebo tablet three times a day for 2 weeks. Patients were asked to record the severity of their pruritus on a visual analogue scale (VAS) twice a day. At the end of the study patients were asked blindly which treatment they had preferred.
                Seventeen patients completed the trial. Pruritus decreased by 16% (95% CI: 0.5-32%) during active treatment and by 25% (95% CI: 9-41%) during treatment with placebo. The change in VAS scores during treatment with ondansetron (P = 0.04) and placebo (P = 0.01) were both significant. Eleven patients expressed a preference, seven for placebo and four for ondansetron.
                Our results show that ondansetron is no better than placebo in controlling renal itch.