Methotrexate elimination in a patient with an orthotopic neobladder with and without a urethral catheter

Placement of a urethral catheter has been recommended to ensure adequate methotrexate elimination in patients with a neobladder; however, the need for this and its impact on methotrexate elimination have not been determined. A 53-year-old man with a cecal continent urinary diversion received intravenous methotrexate 30 mg/m² on two occasions, with and without urethral catheter drainage of the neobladder. Serum methotrexate concentrations declined at a rate that resulted in 24- and 48-hour values falling below the accepted toxic concentration threshold of 5-50 μmol/L and 0.05 μmol/L, respectively. In this man, who received low-dose methotrexate, catheterization of the neobladder did not alter methotrexate elimination sufficiently to justify its cost, risk, and inconvenience.