Abstract

A randomized cross-over study was undertaken to compare nebulized (1) ceftazidime with (2) a combination of gentamicin and carbenicillin, and (3) saline, each given for 4 months, in patients with cystic fibrosis infected with Pseudomonas aeruginosa. Mean peak expiratory flow on ceftazidime, 299 litres/min, and on gentamicin and carbenicillin, 297 litres/min, were greater than on saline, 278 litres/min (P less than 0.02 and P less than 0.05 respectively). Similarly mean forced expiratory volume in 1 second on ceftazidime, 1.70 litres, and on gentamicin and carbenicillin, 1.70 litres, were greater than on saline, 1.48 litres (P less than 0.02 and P less than 0.01 respectively). Mean forced vital capacity on gentamicin and carbenicillin, 2.93 litres, was also greater than on saline (P less than 0.05). We were unable to demonstrate any difference in efficacy between the antibiotic regimens. The patients were admitted to hospital less frequently during the study year compared with the previous year (P less than 0.05). Sixty-nine per cent of patients had a clinically significant (20%) increase in forced expiratory volume in 1 second on an antibiotic regimen compared with that on entry to study, but a minority of patients appear not to respond to this form of treatment.