 Inhaled therapy with antibiotics such as tobramycin, colistin, and aztreonam is often given for months at a time to improve lung function by impeding the growth of colonized bacteria.Inhaled antibiotic therapy helps lung function by fighting infection, but also has significant drawbacks such as development of antibiotic resistance, tinnitus, and changes in the voice.Inhaled levofloxacin may be used to treat "Pseudomonas aeruginosa" in people with cystic fibrosis who are infected.