Repeated sinomenine administration alleviates chronic neuropathic pain-like behaviours in rodents without producing tolerance

Highlights • Spinally injured rats and sciatic nerve injured mice were used to study the effect of repeatedly administered sinomenine on hypersensitivity to mechanical and cold stimuli. • Following repeated administration, the analgesic effect of sinomenine was increased, without development of tolerance. • Sinomenine may be explored as a novel analgesic for treating some forms of chronic neuropathic pain in patients.