Antibiotics and chemotherapeutics in renal lymph. An experimental study in dogs

Renal lymph concentrations of ampicillin, carbenicillin, cephacetrile, cephaloridine, and nitrofurantoin were determined in a total of 28 dogs during constant infusion of the drugs together with [125I]iothalamate and [131I]o-iodohippurate for simultaneous determination of glomerular filtration rate and effective renal plasma flow. The lymph concentrations of the radiolabeled clearance substances, serving as a standard were compared to those of the antimicrobial agents. The lymph concentrations of the four antibiotics were all significantly lower than the respective simultaneous arterial plasma concentrations. The nitrofurantoin lymph concentrations were equal to the simultaneous plasma concentrations. It is concluded that the renal lymph concentrations of antibiotics and chemotherapeutics do not exceed the simultaneous plasma concentrations unless the urine flow is obstructed.