Cayston

Cayston is the brand name for aztreonam for inhalation solution, an antibiotic formulated for inhalation and used to treat chronic infection with Pseudomonas aeruginosa in people with cystic fibrosis (CF). It is administered by nebulization and is part of a broader set of inhaled therapies for CF.

Aztreonam is a monobactam beta-lactam antibiotic that inhibits bacterial cell wall synthesis by binding to penicillin-binding proteins. It is primarily active against Gram-negative bacteria, including Pseudomonas aeruginosa, and is not typically effective against most Gram-positive organisms. Cross-reactivity with penicillins is considered low, but allergy to aztreonam or other beta-lactams is a consideration in treatment planning.

Cayston dosing involves 75 mg of aztreonam inhalation solution given three times daily for a 28-day cycle, followed by 28 days off therapy. The cycles may be repeated based on clinical response and physician guidance. Treatment is delivered using a nebulizer, and patients may be instructed to use a bronchodilator beforehand if airway reactivity is a concern.

Common side effects include cough, nasal congestion, wheezing, throat discomfort, fever, and a foul taste. Bronchospasm can occur, so monitoring for respiratory reactions is advised; hypersensitivity to aztreonam or other beta-lactams is a precaution. Cayston has been incorporated into CF care plans to reduce Pseudomonas burden and related pulmonary exacerbations, often alongside other inhaled antibiotics and CF therapies.

Cayston was approved by the U.S. Food and Drug Administration in 2010 for cystic fibrosis patients with P. aeruginosa infection.