Probenecid interaction with cephalosporins

Agents that may interact with cephalosporins include ethanol, aminoglycosides, anticoagulants, polypeptide antibiotics, probenecid, antacids, H2antagonists, iron... 

Probenecid has been reported to inhibit renal elimination of many drugs acyclovir (325,326), allopurinol (327), bumetanide (328), cephalosporins (329-334), cidofovir (335), ciprofloxacin (336), famotidine (337), fexofenadine (338), furosemide (339), and oseltamivir (Ro 64-0802) (340). Recent studies have elucidated that probenecid is a potent inhibitor of renal organic anion transporters (OAT1 and OAT3) with the Ki values lower than the unbound plasma concentration of probenecid, indicating the interaction with probenecid includes inhibition of the basolateral uptake process mediated by OAT1 and/or OAT3. 

The increased levels and decreased renal excretion of clinafloxacin caused by probenecid are not considered large enough to warrant dosage adjustment," and most of the changes seen with the other quinolones were of a similar magnitude. However, caution has been advised in the presence of other drugs that may also compete for renal excretion (such as some penicillins or cephalosporins). " Grepafloxacin, moxifloxacin, sparfloxacin, and probably ofloxacin, appear not to interact. 

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