In a randomized prospective study, 66 patients with serious
bacterial infections--mainly lower
respiratory tract infections--were treated with either
imipenem plus
cilastatin (32 patients) or
ciprofloxacin (34 patients); 30 patients in each group were evaluable for efficacy. Substantial underlying disease was present in most of the patients; pathogens isolated prior to treatment (77 isolates) consisted mainly of members of the family Enterobacteriaceae, Pseudomonas aeruginosa, Staphylococcus aureus, Haemophilus influenzae, and streptococci. Of the etiologic bacteria, 67% were eradicated by
ciprofloxacin treatment and 79% by
imipenem therapy; however, two patients (6.7%) failed in the
ciprofloxacin group, and six patients (20%) did not respond to
imipenem treatment (P = 0.25). All patients with therapeutic failures suffered from severe fatal underlying diseases, which had substantial impact on the outcome of treatment. Therapeutic
drug monitoring in the
ciprofloxacin patients revealed higher concentrations in serum at days 4 and 8 in comparison with day 1 of treatment, indicating that steady-state conditions were reached between days 1 and 4. The total number of side effects was relatively high--eight
imipenem patients (25%) and six
ciprofloxacin patients (18%) had reactions. Treatment had to be discontinued due to adverse reactions for three
ciprofloxacin patients and two
imipenem patients. Major side effects in both groups were gastrointestinal and central nervous system-related symptoms. In terms of clinical and bacteriological efficacy and safety, there was no statistical difference between the two groups, and both groups gave good to excellent results for
bacterial infections that were difficult to treat.