Nalfurafine hydrochloride: a new drug for the treatment of uremic pruritus in hemodialysis patients.

Uremic pruritus in hemodialysis patients is intractable and no effective treatments have been established yet. Although the precise mechanism of the pruritus is still unclear, accumulating evidence suggests that activation of the micro-opioid receptors may induce pruritus in hemodialysis patients. On the other hand, activation of kappa-opioid receptors is known to control or inhibit the signals activated through micro-opioid receptors; therefore, it was expected that kappa-opioid receptor agonists would be able to reduce pruritus in patients undergoing hemodialysis. Nalfurafine hydrochloride is a novel derivative of the opioid receptor antagonist naltrexone. Nalfurafine hydrochloride is a selective kappa-opioid receptor agonist and has a potent antipruritic effect on various types of pruritus through central kappa-opioid receptor activation in non-clinical pharmacological studies. Moreover, clinical studies have demonstrated that nalfurafine hydrochloride possesses efficacy and safety in hemodialysis patients with uremic pruritus. In this review, we provide a detailed description of the activity of nalfurafine hydrochloride using published data of in vitro, in vivo nonclinical pharmacological and clinical studies in hemodialysis patients with uremic pruritus.