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.
Treatment of pruritus in primary biliary cirrhosis with rifampin. Results of a double-blind, crossover, randomized trial.
The cause of pruritus of cholestasis is unknown. We have hypothesized that pruritus may be caused by an indirect effect of high hepatic concentrations of toxic bile acids. To test this hypothesis, we have conducted a double-blind, controlled, crossover clinical trial of rifampin, an agent that inhibits hepatic bile acid uptake and may detoxify hepatic bile acids by stimulation of mixed-function oxidases. Nine patients with primary biliary cirrhosis received 300-450 mg/day of rifampin and placebo sequentially, in random order. Each treatment was administered for 14 days, with a 14-day washout between treatments. Endpoints included patient preference, changes in a daily visual analogue scale pruritus score, and amount of cholestyramine ingested. Antipyrine elimination rates and serum bile acids were tested at the end of each treatment period. All 9 patients completed the trial and 8 of them preferred rifampin to placebo (p = 0.03). There were no adverse reactions. Visual analogue scale pruritus scores showed no significant placebo response or any effect from the order of treatment, but did show a highly significant reduction in pruritus in response to rifampin (p less than 0.002). This effect was evident within the first week of rifampin treatment. Rifampin produced a 33% reduction in antipyrine plasma half-life, but no change in fasting total serum bile acids. Cholestyramine usage did not change significantly. We conclude that rifampin is useful for short-term relief of pruritus in primary biliary cirrhosis; however, the mechanism of this effect is unknown. Longer trials are needed, as are trials in other cholestatic disorders.