Dimesna is a prodrug of mesna (dimer of mesna). Dimesna is reduced to mesna in the kidneys. Dimesna does not prevent cellular damage by metabolites of ifosfamide and cyclophosphamide in the renal tubular cell line LLC-PK1. Dimesna is a mucolytic agent used to alleviate toxic side effects of antitumor drugs. The organic acid transporter OAT4 on the luminal side of the proximal renal tubule facilitates the reabsorption of dimesna, and therefore its reduction to mesna, whereas the multidrug and toxin extrusion protein MATE1, the multidrug resistance protein MRP2, and P glycoprotein facilitate the efflux of mesna and/or dimesna back into the lumen; dimesna may also be excreted unchanged by MRP4. It has therefore been suggested that polymorphism of these renal transport proteins or transporter-mediated drug-drug interactions may reduce the efficacy of mesna and dimesna.