Some antibiotics DO have adjuvants that prolong excretion. Examples are probenecid that was added to penicillin formulations to ensure there was enough supply.

Some antibiotics DO have adjuvants that prolong excretion. Examples are probenecid that was added to penicillin formulations to ensure there was enough supply. Imipenem (another antibiotic) is given with cilastin to reduce clearing of the drug by the kidney. Patients get into trouble when their renal clearance is already poor from long-standing kidney disease, so the potential is there for the drug to build to a level where it exhibits effects beyond its therapeutic intent (ie toxicity).