Which of the following is true about the use of tobramycin?

1. It is primarily used by patients with cystic fibrosis.
2. It is intended to manage chronic infections with Pseudomonas aeruginosa.
3. It prevents deterioration of lung function due to recurrent infections.
4. It has very good lung bioavailability.
5. It is associated with a high rate of bacterial resistance.
a. 1 and 2 only
b. 3 and 5 only
c. 1, 2, 3, and 5 only
d. 1, 2, 4, and 5 only

ANS: C
Patients with cystic fibrosis (CF) have chronic respiratory infection with Pseudomonas aeru-ginosa, as well as other microorganisms. Such chronic infection causes recurrent acute respiratory infections and deterioration of lung function. With the exception of the quinoline derivatives such as ciprofloxacin, antibiotics such as the aminoglycosides (e.g., tobramycin), which are effec-tive against Pseudomonas organisms, have poor lung bioavailability when taken orally. Conse-quently, such antibiotics must be given either intravenously or by inhalation. The aminoglycoside, tobramycin, has been approved for inhaled administration and is intended to manage chronic in-fection with P. aeruginosa in CF. Goals of therapy are to treat or prevent early colonization with P. aeruginosa and maintain present lung function or reduce the rate of deterioration. The emer-gence of bacterial resistance was not seen in clinical trials with inhaled tobramycin.