Renal tubular transporters and antiviral drugs: an update.

Systemic disposition of antiviral drugs partly depends on renal handling of these compounds. There are some known, functionally characterized anionic and cationic transporters with varying substrate specificities for those drugs: human organic anion transporter (OAT) family (hOAT1-3) and human organic cation transporter (OCT) family (hOCT1-3), which mediate the intracellular flux, and adenosine 5'-triphosphate (ATP) binding cassette transporter family (P-glycoprotein, MRP2-5), which mediate the cellular efflux of antiviral drugs. The peptide transporter (PEPT1-2) mediate bi-directional facilitated diffusion of valacyclovir. All these transporters are expressed in the kidney. Organic anion and cation transporters primarily localize to the basolateral membrane of renal epithelial cells while ATP-binding cassette transporters primarily localize to the apical membrane. These transporters work in concert to mediate renal intracellular concentration of occurring antiviral drugs. Along with drug-metabolizing enzymes, these transporters are important determinants of drug effectiveness and toxicity. This review examines the role that these transporters play in renal disposition of antiviral drugs.