Nalfurafine (subcutaneous injection; 0.015 mg/kg) combines with EOM-salvinorin-B produces spinal antinociception equivalent to 5 mg/kg, it also enhances the supraspinal analgesic effect of 5 mg/kg morphine.Nalfurafine (subcutaneous injection; 4 μg/kg) causes a dose-dependent increase of the inhibition of the acetic acid-induced abdominal constriction,and the inhibition of the abdominal constriction reaches its peak 30 min after injection, gradually declined and returned to the pre-injection level 4 hr after.
Nalfurafine hydrochloride was launched on March of 2009 in Japan as the first in class non-narcotic opioid drug for intractable itch caused by hemodialysis. It showed significant opioid κ-agonist activity and induced neither aversion nor preference in rats on the CPP (Conditioned Place Preference) test. A new therapeutic agent for the treatment of uremic pruritus in hemodialysis patients.