Effectiveness and Safety of 0.025% Capsaicin Gel for Hemodialysis -related Pruritus : A Randomized, Double - blind, Placebo - controlled Study-ประสิทธิผลของยา 0.025% แค็บไซซินชนิดเจลในการรักษาภาวะคันในผู้ป่วยไตวายเรื้อรัง การศึกษาแบบสุ่ม เปรียบเทียบกับกลุ่มควบคุมโดยปิดสองข้าง

Abstract

             Pruritus is a significant symptom among patients recieving hemodialysis. Local application of capsaicin depletes the peripheral neurons of substance P and calcitonin gene-related peptide (CGRP) and may block the conduction of pain or pruritus. Capsaicin was effective for pain treatment yet without supportive scientific data for pruritus. This randomized, double-blind, placebo-controlled study was to assess the effectiveness and safety of 0.025 percent capsaicin gel in the treatment of hemodialysis- related pruritus. Thirty chronic uremic pruritic patients, undergoing hemodialysis at Chachoengsao hospital. Patients were randomly allocated to 0.025 percent capsaicin gel group and placebo group. Fifteen patients in 0.025 percent capsaicin gel group with moderate (n=12) to severe (n=3) pruritus and fifteen patients in placebo group with moderate (n=11) to severe (n=4) pruritus were examined in a double-blind, placebo-controlled study and 29 of them completed the study. Topical agent of capsaicin or placebo base gel was applied to localized area of pruritus 3 times a day for 4 weeks. The main intensity of pruritus measured by Thai-questionnaire, based on the short form of the McGill Pain Questionnaire (Th-SF-MPQ), at 0, 4 weeks and visual analogue scale (VAS), at 0,1,2,3,4 weeks after treatment. The severity of treatment-related side effects were evaluated. The results showed capsaicin was significantly more effective reducing of pruritus severity than placebo (unpaired t-test, p<0.05) but not in quality of life score and no serious side effect was noted during the study. In summary, the present study indicates topical treatment of hemodialysis-related pruritus with 0.025 percent capsaicin gel is demonstrated to markedly improve the pruritus of these patients.

Key words: capsaicin, hemodialysis- related pruritus