MTX大量療法時のMTX濃度低下遅延に対する柴苓湯の効果

Effect of Chai-ling-tang (Sairei-to) for Methotrexate Concentration Degradation Delay by Methotrexate High-dose Therapy

Ⅰ．はじめに

　脳原発悪性リンパ腫患者に対する化学療法として，methotrexate（MTX）大量化学療法が行われるが，しばしばその濃度低下が遅延しロイコボリン救援療法を延長しなければならないことがある．MTXの排泄を促進する際，利尿作用が強力なフロセミドなどのループ利尿剤を投与すると尿が酸性化し，尿細管にMTXの結晶が沈着し腎不全を起こす恐れがあり使用することができない¹²⁾．いくつかの漢方薬は利尿作用を有し，これまでもいろいろな浮腫性病変（ネフローゼ症候群，肝硬変，妊娠，黄斑浮腫，術後のリンパ浮腫など）に使用されてきた^4,7,8)．そのなかでも柴苓湯は急性の利尿作用があることが報告されている^1,6)．われわれは柴苓湯の利尿効果で，MTXの排泄を促進させ，その濃度低下遅延を防ぐことができるか検討を行った．

　When methotrexate (MTX) salvage chemotherapy is performed for primary brain malignant lymphoma, use of leucovorin rescue must often be extended due to delays in the degradation of blood concentration. We examined whether delay in MTX blood concentration degradation could be prevented by chai-ling-tang (Sairei-to) which has diuretic action.

　In the five cases examined were MTX blood concentration 72 hours after MTX administration was more than 1×10^-7M. A single dose of 3g of chai-ling-tang was administered three times on the day the MTX salvage chemotherapy was subsequently performed.

　MTX blood concentration at 72 hours post MTX administration and subsequent chai-ling-tang administration was less than 1×10^-7M in all five cases. In addition, urea nitrogen and creatinine levels in serum increased and creatinine clearance decreased following MTX administration, however these changes induced by MTX administration were reduced by chai-ling-tang administration.

　Chai-ling-tang was effective in preventing an MTX deferent delay in MTX high-dose therapy by improving renal blood flow.