Drug Interaction Report

Consumer information for this interaction is not currently available.

MONITOR: Coadministration with probenecid may increase and prolong the serum concentrations of some cephalosporins. The proposed mechanism is competitive inhibition of renal tubular secretion by probenecid, although data suggest other mechanisms may also be involved. The magnitude of interaction appears to be dependent on the dose and timing of administration of probenecid, with greater pharmacokinetic changes reported when larger doses of probenecid are used and when probenecid is administered with or immediately before cephalosporin administration. Increases of 30% to more than 100% in systemic exposure and half-life, and decreases of approximately 30% to 60% in clearance, have been reported for various cephalosporins studied.

MANAGEMENT: Although probenecid has been used therapeutically to enhance serum levels of various beta-lactam antibiotics, the potential for increased adverse effects should be considered when probenecid is added to existing cephalosporin therapy, particularly when the latter is given at high dosages or to patients who are elderly or have renal dysfunction. Adjustment of the cephalosporin dosage may be required in accordance with the individual product labeling. For example, cefotaxime dosage should generally not exceed 6 grams/day when administered with probenecid. Probenecid reportedly does not affect the elimination of ceftazidime or ceftriaxone.