Effect of the rectal administration of pregabalin

• Project/Area Number: 16K09236
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Research Field: General internal medicine(including psychosomatic medicine)
• Research Institution: Shinshu University
• Principal Investigator: Mamiya Keiko 信州大学, 医学部附属病院, 教授(特定雇用) (80231603)
• Project Period (FY): 2016-04-01 – 2020-03-31
• Project Status: Completed (Fiscal Year 2019)
• Budget Amount: ¥4,420,000 (Direct Cost: ¥3,400,000、Indirect Cost: ¥1,020,000); Fiscal Year 2018: ¥1,560,000 (Direct Cost: ¥1,200,000、Indirect Cost: ¥360,000); Fiscal Year 2017: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000); Fiscal Year 2016: ¥1,430,000 (Direct Cost: ¥1,100,000、Indirect Cost: ¥330,000)
• Keywords: プレガバリン / ラット / 注腸投与 / 神経障害性疼痛 / 注腸 / 内科 / 緩和医療

Outline of Final Research Achievements

We use the PSNL (Partial sciatic nerve ligation) model for the rat neuropathic pain. Rats were divided it into three groups and dissolved 6 mg/kg and 12 mg/kg of pregabalin with 0.5 mL of saline,and also in the control group 0.5 mL of saline by rectal administration.Thirty, 60 and 120 minutes after administrate the solution , we tasted the escape threshold for the mechanical stimulation and Dynamic Weight Bearing(BIOSEB, France) for the observation of spontaneous pain.
One hundred twenty minutes after the administration the pregabalin, the escape threshold for the mechanical stimulation significantly increased compared with the control group. Ipsi/contralateral hind paws weight ratio and the weight ratio of the diseased side among the total weight was significantly increased as compared with a control in 12 mg/kg of pregabalin group 60 minutes after administration. It was suggested that the rectal administration of pregabalin improved a neuropathic pain.

Academic Significance and Societal Importance of the Research Achievements

プレガバリンは神経障害性疼痛に効果がある薬剤であるが、現在内服薬のみしかなく、注射薬や坐薬は商品化されていない。緩和ケアの診療の場面では、プレガバリンでコントロールできていた痛みが、がんの終末期に内服が出来なくなることで、痛みのコントロールに難渋する症例も少なくない。
今回、プレガバリンの注腸投与が神経障害性痛を改善することが証明された。この結果を臨床応用することで、特に終末期の経口摂取不能な神経障害性痛を有するがん患者の難治性の痛みをプレガバリンの注腸投与で治療することが可能となり、患者にとっても医療者にとっても大きな福音となる。