Moderate
Established
説明
Amoxicillin can reduce the renal clearance of methotrexate by inhibiting tubular secretion, increasing methotrexate plasma levels and risk of toxicity.
機序
Penicillin-class antibiotics including amoxicillin inhibit organic anion transporters (OAT1/OAT3) in the renal proximal tubule that mediate active secretion of methotrexate, prolonging its elimination half-life.
臨床的意義
Case reports and a small prospective study document 2- to 3-fold methotrexate AUC increases with beta-lactam co-administration; neutropenia and mucositis have occurred.
対処法
Avoid amoxicillin around high-dose methotrexate infusions; if co-administration is unavoidable with low-dose methotrexate, monitor CBC and renal function closely.