[Efficacy of traditional herbal medicine, Yokukansan on patients with neuropathic pain].
BACKGROUND
Neuropathic pain that is the chronic, severe, and intractable pain, interferes with activities of daily living (ADL) and consequently reduces quality of life (QOL). We reported the efficacy of Yokukansan in patients with neuropathic pain, including acute herpetic pain, postherpetic neuralgia, central poststroke pain, post-traumatic spinal cord injury pain, thalamic syndrome, complex regional pain syndrome and symptomatic trigeminal neuralgia. Yokukansan was more effective compared with traditional medicines, such as tricyclic antidepressants, carbamazepine, gabapentin, and opioids etc., which are recommended to treat neuropathic pain. Recently, effects of Yokukansan is reported on the behavioral and psychological symptoms of dementia (BPSD) in elderly patients with dementia. Repeated administration of Yokukansan decreases expression of 5-hydroxytryptamine (5-HT) 2A receptors in the prefrontal cortex in mice, and Yokukansan also protects destruction of myelin sheaths in rats with thiamine deficient-induced encephalopathy. Mechanism of effectiveness of Yokukansan on neuropathic pain has not been established; however, efficacy of Yokukansan on neuropathic pain has been shown clinically.


CONCLUSIONS
As far as we know, this is the first report that Yokukansan was effective on neuropathic pain. Yokukansan without serious adverse reactions may be a possible medicine for treatment of neuropathic pain in future.
Department of Anesthesiology and Pain Medicine, Juntendo University School of Medicine, Tokyo 113-8421.
Yoshitaka
Y
Nakamura
Keiko
K
Tajima
Izumi
I
Kawagoe
Masanori
M
Kanai
Hiromasa
H
Mitsuhata
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000818:Animals; D002908:Chronic Disease; D004365:Drugs, Chinese Herbal / Q000494:pharmacology / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D051379:Mice; D008875:Middle Aged; D009186:Myelin Sheath / Q000473:pathology; D009437:Neuralgia / Q000188:drug therapy*; D008517:Phytotherapy; D017397:Prefrontal Cortex / Q000378:metabolism; D051381:Rats; D044402:Receptor, Serotonin, 5-HT2A / Q000378:metabolism; D013832:Thiamine Deficiency / Q000473:pathology
D004365:Drugs, Chinese Herbal; D044402:Receptor, Serotonin, 5-HT2A; C524644:Yi-Gan San