Tobramycin in treatment of infections due to Pseudomonas aeruginosa in patients with cystic fibrosis.

The effectiveness and safety of tobramycin against infections due to Pseudomonas aeruginosa 
in patients with cystic fibrosis were studied in 15 patients with 
moderate-to-severe exacerbation of chronic pulmonary infection. Seventeen courses of treatment were 
given. Tobramycin (5-7.5 mg/kg per day) was administered intravenously in three 
divided doses per day (seven to 21 days). All specimens of 
sputum yielded moderate-to-heavy growth of P. aeruginosa; all isolates were inhibited 
by 4 mug of tobramycin/ml, and in seven cases isolates were 
not inhibited by 4 mug of gentamicin/ml. The mean levels of 
tobramycin in the blood were 4.4 mug/ml 0.5-1 hr and 0.8 
mug/ml 7.5-8 hr after administration. All patients received an antistaphylococcal agent 
before, during, and after therapy. All patients except for two received 
750 mg of carbenicillin/kg per day intravenously in six divided doses 
and 1 g of carbenicillin in a mask for inhalation three 
times a day. Both clinical and radiological improvement was noted in 
all patients. The white blood cell count, which was elevated in 
seven patients, returned to normal, and levels of blood gases improved. 
P. aeruginosa was eliminated from the sputum in five cases. No 
adverse side effects were noted. 