mucolytics

Mucolytics are medications designed to reduce the thickness and stickiness of mucus in the airways, helping to clear secretions through coughing or suction. They are used when mucus production is excessive or abnormally viscous, contributing to airway obstruction and infection in diseases such as chronic bronchitis, bronchiectasis, chronic obstructive pulmonary disease (COPD), cystic fibrosis, and post-infectious airway conditions.

Most mucolytics work by altering the physical properties of mucus. Some, like N-acetylcysteine and carbocisteine, break disulfide bonds within mucus glycoproteins, reducing viscosity. Others, such as ambroxol and bromhexine, influence mucus production and the composition of mucus, sometimes promoting hydration and easier expectoration. Some agents also have antioxidant properties, with N-acetylcysteine replenishing glutathione stores in tissues.

Commonly used mucolytics include N-acetylcysteine, carbocisteine, bromhexine, and ambroxol. They are available in oral and inhaled (nebulized) formulations, and the route of administration may affect the site and magnitude of action. Dosing and duration vary by product and condition, so clinicians follow local guidelines and product labeling.

Adverse effects are generally mild but can include gastrointestinal upset (nausea, vomiting, diarrhea) and, with inhaled forms, bronchospasm or coughing. Hypersensitivity reactions are possible but uncommon. Mucolytics are not antibiotics; they aid mucus clearance but do not treat infection themselves. Evidence for benefit varies by condition, with clearer utility in diseases characterized by thick mucus and poor clearance, while routine use in some chronic lung diseases remains a topic of ongoing evaluation.