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.
The potent bile acid sequestrant colesevelam is not effective in cholestatic pruritus: results of a double-blind, randomized, placebo-controlled trial.
Colesevelam is an anion-exchange resin with a 7-fold higher bile acid-binding capacity and fewer side effects than cholestyramine, the current first-line treatment option for cholestatic pruritus. The aim of this trial was to compare the effects of colesevelam and a placebo in patients with cholestatic pruritus. In a randomized, double-blind, investigator-initiated, multicenter trial, patients with cholestatic pruritus, both treatment-naive and previously treated, received 1875 mg of colesevelam or an identical placebo twice daily for 3 weeks. The effect on pruritus was assessed with daily visual analogue scales, quality-of-life scores, and evaluations of cutaneous scratch lesions. The predefined primary endpoint was the proportion of patients with at least a 40% reduction in pruritus visual analogue scale scores. Thirty-eight patients were included, and 35 were evaluable: 17 took colesevelam, 18 took the placebo, 22 were female, 8 were treatment-naive, 14 had primary biliary cirrhosis, and 14 had primary sclerosing cholangitis. The mean serum bile acid levels were comparable between the groups before treatment (P = 0.74), but they were significantly different after treatment (P = 0.01) in favor of patients treated with colesevelam. Thirty-six percent of patients in the colesevelam group reached the primary endpoint versus 35% in the placebo group (P = 1.0). There were no significant differences between the groups with respect to pruritus scores, quality-of-life scores, and severity of cutaneous scratch lesions. Mild side effects occurred in one colesevelam-treated patient and four placebo-treated patients.
                Although colesevelam significantly decreased serum bile acid levels, this trial was unable to demonstrate that it was more effective than a placebo in alleviating the severity of pruritus of cholestasis.