The advantages of a demulcent and an expectorant combination for an acute cough. 

An acute cough is a common symptom of acute bronchitis or the common cold, often significantly impacting patients’ quality of life (QoL) and work productivity. Most cases are self-limiting and are of viral origin, making antibiotic treatment inappropriate due to side effects and resistance risks. Symptomatic treatment is preferred and often involves self-medication.  

Cough acts as a defence mechanism to prevent harmful substances from entering the tracheobronchial tree and to expel secretions. Recent research focuses on the "urge to cough" (UTC) sensation that precedes the motor act of coughing, indicating that sensory nerves in the pharynx might also trigger the cough reflex.  

DRY VS WET COUGH  

Dry coughs are usually caused by viral URTIs, acute bronchitis, irritants, and allergies, while wet coughs often result from URTIs, post-nasal drip, and pneumonia. The common cold typically starts with a sore throat and dry cough, progressing to a productive cough, and then back to a dry cough as the illness resolves.  

DEMULCENTS  

Marshmallow root extract (Althaea officinalis L.) is a herbal demulcent traditionally used for oral or pharyngeal irritation and associated dry cough. Demulcents like marshmallow root dry extract form a protective barrier on the pharynx, soothing inflammation and irritation, and relieving cough by coating sensory receptors to reduce the UTC.  

Marshmallow root dry extract has proven efficacy in reducing cough intensity and frequency across various clinical trials. Dr Peter Voitl, a specialist paediatrician, and paediatric expert for the European Medicines Commission for Paediatrics with special focus on phytotherapy, advocates for demulcents like marshmallow root extract as a first-line treatment for cough due to their coating effect, which is beneficial for both children and adults.  

EXPECTORANTS  

Thyme herb extract is a herbal expectorant with secretolytic and mucolytic properties, which helps improve mucociliary clearance and has a spasmolytic effect to help open airways. Thyme has been used to treat various respiratory disorders for, including coughs from colds and bronchitis. Thyme extract stimulates bronchial gland function, reduces surface tension, and improves mucociliary clearance.  

A cough syrup combining a demulcent (marshmallow root extract) and an expectorant (thyme herb extract) provides a distinct advantage for patients due to its dual action. The demulcent acts locally within the pharynx to reduce the UTC, while the expectorant works systemically within the lungs to thin and clear mucus. This complementary action effectively relieves both productive and non-productive coughs. 

SOURCE: The advantages of a demulcent and an expectorant combination for an acute cough – Inova CPD Article