中等量メソトレキサート治療の血中濃度に及ぼすプロトンポンプ阻害薬，脱水，急性腎障害の影響

Abstract

Recent studies have reported methotrexate (MTX) delayed excretion in the case of co-administration of proton pump inhibitor (PPI) in high-dose MTX therapy. We investigated whether PPI influenced the serum concentration of MTX (MTX-con) in intermediate-dose MTX chemotherapy. We also investigated the relation between MTX-con and blood urea nitrogen (BUN) / serum creatinine (SCr) ratio before the treatment, which is a kind of laboratory indicator of dehydration. MTX-con and SCr increase after the treatment. We examined MTX-con for 36 cycles in 19 candidates in our institution. Co-administration of PPI was observed in 8/36 (22%). Average MTX-con at 48 hr after MTX administration with and without co-administration of PPI was 0.32 ± 0.12 μM and 0.41 ± 0.37 μM respectively (P = 0.92). A BUN/SCr ratio indication over 20 before therapy was observed in 10/36 (28%). Average MTX-con at 48 hr after MTX administration was 0.21 ± 0.14 μM in the BUN/SCr ratio 20 and over group, 0.46 ± 0.36 μM in the BUN/SCr ratio under 20 group (P < 0.01). SCr increased over 0.3 mg/dL after MTX administration was observed in 4/36 (11%). Average MTX-con after 48 hr MTX administration was 0.72 ± 0.6 μM in the SCr 0.3 and over group, 0.35 ± 0.27 μM in the SCr under 0.3 mg/dL group (P < 0.05). Co-administration of PPI is not associated with MTX delayed excretion and BUN/SCr ratio before the treatment and SCr increase after the treatment was suggested as a possible factor in MTX-con influence.