Intractable itching

A patient with intractable itching would best respond to which of the following ... 

Mechanisms of itch are both peripheral and central. Impulses pass along the same nerve fibres as those of pain, but the sensation experienced differs qualitatively as well as quantitatively from pain. In the CNS endogenous opioid peptides are released and naloxone can relieve some cases of intractable itch. Local liberation of histamine and other autacoids... 

Patients on hemodialysis often complain of an intractable pruritus (uremic pruritus). Indeed, the consequent sleep disorder can impair the quality of life. Clinical and preclinical data suggested that the p opioid system induced itching, but not the k system. The antipruritic efficacy of nalfurafine hydrochloride (general name of TRK-820) was demonstrated for patients on hemodialysis in two multicenter, randomized, double-blind, placebo-controlled, clinical studies in Europe [66]. 

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