Kozono H, et al. - In this post-marketing surveillance study, researchers tested nalfurafine, a selective κ-opioid receptor agonist, as a treatment option for intractable pruritus in patients undergoing hemodialysis. They found that in real-world clinical settings, oral nalfurafine hydrochloride (from 2.5 μg/day to a maximum of 5.0 μg/day) continued to be a safe and effective treatment option for intractable pruritus in hemodialysis patients.

• A surveillance was performed including hemodialysis patients with intractable pruritus from institutions in Japan who received oral nalfurafine hydrochloride between January 2010 and December 2013.
• Surveillance was completed in July 2015.
• Researchers gathered and analyzed: safety data during 1 year after nalfurafine treatment onset, and efficacy data of nalfurafine evaluating the first 12-week treatment period and the following period until 1 year after the initial dose of nalfurafine (using global assessment of the itch improvement by the physician, Visual Analog Scale, and the Shiratori’s severity scores).

• For safety, a total of 3,762 patients were analyzed.
• A total of 402/3,762 (10.69%) patients experienced adverse drug reactions.
• Insomnia (127/3,762 [3.38%] patients), constipation (34 [0.90%]), somnolence (32 [0.85%]), dizziness (23 [0.61%]), nausea (13 [0.35%]), and malaise (9 [0.24%]) were recognized as the most frequent adverse drug reactions.
• Dependence on nalfurafine was not detected in any patient.
• Researchers observed that nalfurafine demonstrated efficacy in 82.50% (2,880/3,491) of patients during the first 12 weeks and in 84.95% (2,167/2,551) on treatment during the subsequent period until 1 year after nalfurafine treatment initiation.
• They found statistically significant decreases in the Visual Analog Scale and the Shiratori’s severity scores (p<0.001).