Clinical Benefit of Mucolytics in the Treatment of Upper Respiratory Tract Infections

Introduction

The mentioned mucolytics are recognized drugs used in the therapy of upper respiratory tract infections. All lead to symptomatic relief of productive cough. These substances share many properties, but have some differences, which are summarized by the authors of the presented work based on available evidence.

The review is based on clinical studies retrieved from the Medline database and other databases dedicated to the efficacy and safety of these mucolytics, without time and design restrictions.

Characteristics of Individual Mucolytics

Ambroxol has been on the market for nearly 50 years in many galenic forms. It exhibits mucokinetic properties and stimulates surfactant secretion. It has demonstrated secretolytic, antioxidant, and anesthetic effects explaining its efficacy in the treatment of upper respiratory tract infections. It has been associated with the risk of allergic reactions and severe skin adverse reactions. No interactions with other drugs have been proven.

Bromhexine is also available in various galenic forms. It has shown effects on mucus production, sputum quality and quantity, ciliary activity, and the severity and frequency of cough, including subjectively easier expectoration of mucus. Concurrent administration likely increases antibiotic penetration. As with ambroxol, there is a warning for allergic reactions and severe skin adverse reactions.

Erdosteine has proven mucolytic and antioxidant effects. It reduces the frequency and severity of cough and sputum viscosity more than placebo and reduces sputum adhesiveness more than ambroxol. Most studies involve patients with COPD and chronic bronchitis. In 2 studies on the pediatric population with acute respiratory tract infection, the beneficial effects of erdosteine in combination with amoxicillin were proven. Its tolerability is generally good, with heartburn being the most common adverse event. No specific drug interactions have been described.

Carbocisteine and N-acetylcysteine are also available in different forms. They break disulfide bridges between macromolecules in mucus, reducing its viscosity. They also have antioxidant effects. They are mainly used in COPD and chronic bronchitis. Published evidence on their efficacy in pediatric patients with acute bronchopulmonary disease is limited, and paradoxical respiratory adverse reactions have been described with systemic administration. This skews the benefit-risk ratio in the pediatric population.

Sobrerol has been on the market for almost 50 years. It increases mucus production and ciliary motility, thus improving mucociliary clearance. It also boosts free radical scavenging. Its efficacy has been proven in both adults and children with acute and chronic respiratory diseases. It exhibits synergistic effects with antibiotics and increases the efficacy of paracetamol. The most common adverse events are gastrointestinal issues and allergic reactions. However, it is safe even when administered to children.

Mucolytics are generally not recommended for children under 2 years of age.

Conclusion

All mucolytics in this review showed comparable efficacy in the symptomatic treatment of productive cough. Their clinical benefits include mucolytic, anti-inflammatory, and antioxidant effects. They also have a good safety profile, but the warnings mentioned for ambroxol and bromhexine apply, and the administration of carbocisteine and N-acetylcysteine should be monitored in pediatric patients.

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Source: Scaglione F., Petrini O. Mucoactive agents in the therapy of upper respiratory airways infections: is it fair to describe them just as mucoactive? Clin Med Insights Ear Nose Throat 2019 Jan 9; 12: 1179550618821930, doi: 10.1177/1179550618821930.