Aztreonam is primarily used as an antibiotic to treat infections caused by Gram-negative bacteria. It is particularly effective against Pseudomonas aeruginosa, making it a critical option for patients with cystic fibrosis who suffer from respiratory infections. The drug is administered via inhalation, intravenous injection, or intramuscular injection, depending on the severity and type of infection. In hospital settings, it is often used to treat complicated urinary tract infections, intra-abdominal infections, and lower respiratory tract infections. Its targeted action against Gram-negative bacteria minimizes disruption to the normal gut flora, reducing the risk of secondary infections like Clostridioides difficile. Aztreonam is also a preferred choice for patients allergic to penicillin or cephalosporins due to its distinct chemical structure, which avoids cross-reactivity.