神経障害性疼痛における個人差を考慮した治療法の模索

抄録

Although the number of needed to treat (NNT) for pharmacotherapy is less than three in patients with acute pain, it is reportedly three or higher in patients with neuropa­thic pain. That might be caused partly by large differences in patients’ characteristics, genetics, and psychosocial factors, in addition to individual differences in pain mechanisms, pharmacokinetics, and pharmacodynamics in neuropathic pain. Therefore, an individualized pharmacotherapy is crucial for better analgesic effects for neuropathic pain. Previous studies using the quantitative sensory testing (QST) reported that neuropathic pain characteristics are classified into three mechanistic subgroups: sensory loss with deafferentation, thermal hyperalgesia with peripheral sensitization, and mechanical hyperalgesia with central sensitization. Pain symptoms described in the neuropathic pain symptom inventory (NPSI) were also divided into three sensory phenotypes of pinpointed pain, evoked pain, and deep pain. Analgesic efficacies of each drug were reportedly different in each group. Other analysis methods using psychological, chemical, and genetic characteristics also have been examined to individualize the analgesic effects on neuropathic pain. Further investigations, however, are still needed to develop an individualized pharmacotherapy reducing the NNT in patients with neuropathic pain.