Effect of Lamivudine on Uptake of Organic Cations by Rat Renal Brush‐Border and Basolateral Membrane Vesicles

The effect of lamivudine on uptake of a representative organic cation, tetraethylammonium (TEA), by rat renal brush-border membrane vesicles (BBMV) and basolateral membrane vesicles (BLMV) has been investigated. The pH-driven uptake of TEA by BBMV (pHin = 60, pHout = 7.5) was inhibited by lamivudine. The IC50 value (concentration resulting in 50% inhibition) for the concentration-dependent effect of lamivudine on TEA uptake by BBMV after 30 s was 2668 μm whereas IC50 values for cimetidine and trimethoprim were 25 mm, whereas the IC50 values for Cimetidine and trimethoprim were 2116 μm and 445 μm, respectively. These findings suggest that compared with other cationic drugs, such as trimethoprim and Cimetidine, lamivudine is a weak inhibitor of organic cation transport into the tubules by the brush-border and basolateral membranes of renal epithelial cells. It is unlikely lamivudine will have any significant effect on the excretion of co-administered cationic drugs by the renal tubules.