Erythromycin, gentamicin, kanamycin, colistin, oxytetracycline, chlorpromazine, vit C, tetracycline & polymixin B. IV lipids, blood products & protein hydrolysates or other proteinaceous fluids. Chloramphenicol & tetracyclines may antagonize bactericidal effect
in vitro. Probenecid increases serum peak plasma conc & prolongs serum conc of cloxacillin.