Efficacy and safety of long-term (104-week) administration of nalfurafine hydrochloride

Abstract

Pruritus in hemodialysis patients is intractable. This condition has attracted increasing attention as a factor that decreases the QOL and adversely affects the prognosis. Nalfurafine hydrochloride (nalfurafine) became clinically available in March 2009 for the treatment of intractable pruritus in hemodialysis patients. Herein, we investigated the efficacy and safety of a 2-year (104-week) administration of nalfurafine in hemodialysis patients with intractable pruritus that is resistant for alternative treatment. The study involved 13 patients whose visual analogue scale (VAS) scores were≥70 mm or itch severity scale (Shiratori's classification) scores were≥3 (moderate), and who were able to take nalfurafine for 104 consecutive weeks. The initial dose of nalfurafine was set at 2.5 μg/day, and a questionnaire survey including assessment by VAS and Shiratori's classification was periodically conducted. The mean scores of both VAS and Shiratori's classification for daytime and nighttime at week 104 were significantly decreased after nalfurafine administration. The frequency of insomnia also decreased, and the number of patients experiencing insomnia became zero by week 74 and remained so until week 104. There were only 3 patients whose nalfurafine dosage was increased to 5 μg/day because pruritus symptoms did not improve. No attenuation of efficacy resulting from drug resistance was observed. All adverse reactions due to nalfurafine appeared within 2 weeks after nalfurafine administration. These results indicate that nalfurafine is effective and safe for long-term administration.