Cephalosporins in urinary tract infection

Despite their greater cost compared with other antibiotics, the cephalosporins continue to be used in the treatment of urinary tract infections. Most cephalosporins are excreted primarily by the kidney (by glomerular filtration, tubular secretion, or both) and urinary concentrations routinely exceed 1000 mg/L after even a small dose; exceptions include cefoperazone and ceftriaxone which both exhibit significant biliary excretion, and in patients with significant renal dysfunction only minimal concentrations of these drugs may be present in the urine. Although single-dose treatment of uncomplicated lower urinary tract infections with oral cephalosporins has not been as effective as with other antibiotics, cephalexin, cephradine and cefaclor continue to be used. Early clinical trials with cefuroxime axetil also appear promising for short term and single-dose therapy. The parenteral cephalosporins are reserved for use against more resistant strains or in hospitalised patients with upper urinary tract infections, their choice being directed by in vitro susceptibility tests. Newer agents such as ceftazidime and cefsulodin have been shown to be effective in infections due to P. aeruginosa. Recommended cephalosporin dosage regimens for the common urinary tract pathogens are given.