THE PRESENCE OF FOOD AND/OR DAIRY PRODUCTS MAY DECREASE ABSORPTION. MAGNESIUM, ALUMINIUM, CALCIUM, IRON AND ZINC ANTACIDS & FOOD DECREASE NORFLOXACIN ABSORPTION. RIFAMCIN REDUCE SERUM CONCENTRATION. CNS EXCITATION OCCUR WITH CONCURRENT ADMINISTRATION OF QUINOLONES AND NSAIDS. CIPROFLOXACIN AND OTHER QUINOLONES ENHANCING THE EFFECT OF ORAL ANTICOAGULANTS. OPIOID ANALGESICS (PAPAVERETUM) ALSO INTERACTS WITH NORFLOXACIN. QUINOLONES MAY INCREASE THE EFFECTS OF THEOPHYLLINE AND/OR CAFFEINE. ELEVATED SERUM LEVELS OF CYCLOSPORINE HAVE BEEN REPORTED WITH CONCOMITANT USE. DIMINISHED URINARY EXCRETION OF NORFLOXACIN HAS BEEN REPORTED DURING THE CONCOMITANT ADMINISTRATION OF PROBENECID.