Medications for Drying Up a Mucous Cough
For patients with a mucous cough, guaifenesin is recommended as the first-line medication due to its proven effectiveness as an expectorant to loosen phlegm and make coughs more productive. 1
First-Line Treatment Options
Guaifenesin (200-400 mg every 4 hours, up to 6 times daily): Acts as an expectorant by increasing expectorated sputum volume, decreasing sputum viscosity, and improving associated symptoms in patients with productive cough 1, 2
Ipratropium bromide (inhaled): Recommended for cough suppression in patients with URI or chronic bronchitis with substantial benefit 3
Hypertonic saline solution: Recommended on a short-term basis to increase cough clearance in patients with bronchitis 3, 4
Second-Line Treatment Options
Central cough suppressants (codeine, dextromethorphan): Recommended only for short-term symptomatic relief of coughing in chronic bronchitis, not recommended for cough due to URI 3
Peripheral cough suppressants (levodropropizine, moguisteine): Recommended for short-term symptomatic relief in chronic or acute bronchitis, but have limited efficacy and are not recommended for URI-related cough 3
Bromhexine: Functions as a mucolytic agent by increasing serous mucus production, making sputum thinner and less viscous, thereby improving expectoration in conditions with thick mucus 5
Mechanism of Action
Guaifenesin works by loosening mucus in the airways, making coughs more productive. It increases expectorated sputum volume over the first 4-6 days of a productive cough, decreases sputum viscosity, reduces difficulty in expectoration, and improves associated symptoms 3, 1.
Unlike cough suppressants that inhibit the cough reflex, expectorants like guaifenesin help clear mucus from the respiratory tract, addressing the underlying cause of productive cough 1, 6.
Dosing and Administration
- Immediate-release guaifenesin: 200-400 mg every 4 hours, up to 6 times daily 1
- Extended-release guaifenesin: 600-1200 mg every 12 hours, providing convenience with twice-daily dosing 1, 7
Safety Profile
Guaifenesin has a well-established and favorable safety and tolerability profile in adult populations 1, 7. However, it should be used with caution in the following situations:
- Cough that lasts more than 7 days, comes back, or is accompanied by fever, rash, or persistent headache 2
- Cough that occurs with chronic conditions such as smoking, asthma, or chronic bronchitis without proper medical supervision 2
Clinical Considerations and Caveats
Combination products: Over-the-counter combination cold medications (except older antihistamine-decongestant combinations) are not recommended until randomized controlled trials prove they are effective cough suppressants 3
Antihistamines: First-generation antihistamines like diphenhydramine may be considered for cough suppression, especially at night when sedation may be beneficial, and when allergic components are contributing to respiratory symptoms 5
Ineffective agents: Agents that alter mucus characteristics are not recommended for cough suppression in chronic bronchitis 3
Limited evidence: The Cochrane reviews indicate limited evidence for the effectiveness of OTC cough medicines, with studies often showing conflicting results 8, 4
Mucolytics vs. expectorants: While mucolytics (like N-acetylcysteine) depolymerize mucin, they have no proven benefit and carry a risk of epithelial damage when administered via aerosol. Expectorants like guaifenesin increase the volume of airway water or secretion 6
When treating a mucous cough, it's important to recognize that the goal is to facilitate mucus clearance rather than simply suppress the cough, as coughing is a protective mechanism to clear airway secretions 5, 6.