Effect of Oral Cromolyn Sodium on Ckd-Associated Pruritus and Serum Tryptase Level: A Double-Blind Placebo-Controlled Study

Methods. Sixty-two haemodialysis (HD) patients with pruritus were enrolled into the study and were randomly assigned to receive CS or placebo (135 mg three times daily) for 8 weeks. Patients were asked to record the severity of their pruritus on each dialysis session on a visual analogue scale (VAS) during the 8 weeks of treatment and 4 weeks following discontinuation of treatment. Serum tryptase levels were determined at baseline, after 8 weeks of treatment and 4 weeks after discontinuation of treatment.Results. Data were analysed in 21 patients in the CS group and 19 patients in the placebo group that completed the study. A significant difference was seen in the severity of pruritus between the two groups during the period of study. Level of pruritus decreased from 8.48 +/- 2.2 to 0.9 +/- 1.8 after 8 weeks of treatment with CS. Geometric mean of serum tryptase at baseline and 8 weeks after treatment were 21.3 and 19.5 ng/ml for the CS group and 18.03 and 18.2 ng/ml for the placebo group, respectively. Although the geometric mean of tryptase had decreased in the CS group, this decrease was not statistically significant (P = 0.214).Conclusion. CS can significantly reduce the severity of pruritus in HD patients, but this effect is not due to a decrease in serum tryptase level.