Intravenous ciprofloxacin therapy in severe infections

Fifty evaluable patients (34 men and 16 women; mean age, 47 years) with severe infections were given intravenous ciprofloxacin (200 mg every 12 hours) for a mean of 14 days. Therapy was continued with oral ciprofloxacin 500 to 750 mg every 12 hours in 34 cases for a mean of 57 days. The sources of the infections were bone and joint (26 patients), respiratory tract (10 patients), urinary tract (four patients), soft tissue (four patients), abdominal (three patients), bacteremia of unknown origin (two patients), and right-sided endocarditis (one patient). Fifteen patients (30 percent) were bacteremic. Causative organisms included Pseudomonas aeruginosa (32 patients), other gram-negative bacilli (18 patients), and gram-positive cocci (nine patients). Minimal inhibitory concentrations ranged between 0.03 and 1 microgram/ml. Mean peak serum concentrations were 1.58 micrograms/ml (intravenous) and 2 micrograms/ml (oral); mean trough serum concentrations were 0.23 micrograms/ml (intravenous) and 0.32 micrograms/ml (oral). Serum bactericidal activity values achieved after intravenous and oral therapy were similar. Response to therapy was evaluated separately in patients with or without osteomyelitis. In 30 patients with infections other than osteomyelitis, clinical cure was achieved in 27 (90 percent), and therapy failure occurred in three patients. In the 20 remaining patients with osteomyelitis, 15 (75 percent) had a satisfactory response, with apparent cure after a mean follow-up of 11 months, whereas five had therapeutical failure (P. aeruginosa became resistant in four of them). Overall, no major adverse effects were encountered. Superinfection by a resistant P. aeruginosa was observed in three patients. Intravenous ciprofloxacin is an effective and safe agent for the therapy of severe infections caused by susceptible organisms.