Cough, a common symptom, can be categorized as either productive or non-productive. A productive cough expels mucus or phlegm, whereas a non-productive cough does not produce these secretions . The treatment of a cough depends largely on its underlying cause.
For a productive cough, mucoactive medications like expectorants are used. Expectorants aim to increase the volume of airway secretions, thereby enhancing the effectiveness of cough. Guaifenesin, found in products such as Robitussin or Mucinex, is a common over-the-counter expectorant. However, it’s important to note that there is no evidence suggesting their effectiveness in treating lung diseases. Additionally, when combined with cough suppressants like dextromethorphan, there may be a risk of increased airway obstruction. Other treatments like hyperosmolar saline and mannitol powder are used as expectorants in cystic fibrosis .
Mucolytics, which help to break down mucus, include drugs like N-acetylcysteine. However, these drugs have not shown proven benefits and may pose a risk of epithelial damage when administered via aerosol. Mucokinetic agents, on the other hand, can enhance the effectiveness of cough either by increasing expiratory cough airflow or by loosening highly adhesive secretions from airway walls. Aerosol surfactant is a promising mucokinetic medication .
Mucokinetics are drugs that help clear mucus from the airways. They can be divided into two types: expectorants and mucolytics.
Expectorants are drugs that increase the amount and hydration of secretions. This helps facilitate the removal of mucus from the respiratory tract.
Guaifenesin: is a commonly used expectorant found in many cough syrups. It acts by increasing the volume and reducing the viscosity of bronchial secretions. It is generally well-tolerated, with only mild side effects such as nausea, vomiting, and diarrhea.
Potassium iodide: is another expectorant that acts directly by irritating the bronchial glands and indirectly by gastric irritation to increase bronchial secretions. However, prolonged use of potassium iodide can lead to hypothyroidism, interfere with thyroid function tests, and cause acne flare-ups in adolescents. It should not be used in pregnancy or in patients sensitive to iodine.
Mucolytics are agents that dissolve thick mucus and help relieve respiratory difficulties. Mucolytics dissolve various chemical bonds within secretions that help in lowering the viscosity of secretions. Several examples of mucolytics include acetylcysteine, carbocysteine, ambroxol, bromhexine, and dornase alpha.
Dornase alpha: is an enzyme that acts as a mucolytic agent. It is used in the treatment of cystic fibrosis, where there is an excess of thick mucus in the lungs. Dornase alpha works by breaking down the DNA present in mucus, thereby reducing its viscosity and making it easier to clear.
Acetylcysteine and carbocysteine also help in decreasing the viscosity of secretions. They work by breaking down disulfide bonds in mucus, thereby reducing its thickness and making it easier to cough up.
Bromhexine: causes depolymerization of mucopolysaccharides, resulting in making the mucus less viscid (mucolytic). Ambroxol is also a mucolytic drug that is a metabolite of bromhexine. They are used to treat respiratory conditions such as chronic bronchitis and asthma.
In contrast, for non-productive or dry coughs, antitussives, which suppress coughing, are typically used. Specific treatments depend on the cause of the cough. For instance, if the cough is due to an infection, healthcare providers may prescribe antibiotics or antiviral medications. For conditions like GERD (gastroesophageal reflux disease), dietary changes and medications like proton pump inhibitors or H2 blockers might be recommended. It’s also advised to drink water and use humidifiers to ease coughs caused by throat irritation or dryness . Examples of antitussives include codeine, pholcodine, noscapine, and dextromethorphan.
Codeine and pholcodine are opioids that act on the brain to suppress cough. They are used for short-term relief of severe cough. However, they have the potential for addiction and dependence and should be used with caution.
Noscapine: is a non-opioid anti-tussive that works by inhibiting cough impulses in the respiratory tract. It has a mild suppressive effect and is generally well tolerated.
Dextromethorphan: is a non-opioid anti-tussive that acts on the brain to suppress cough. It is used for the treatment of cough associated with upper respiratory infections. It has a low potential for abuse and dependence and is generally considered safe when used as directed.
Disclaimer: This article is for informational purposes only and should not be taken as medical advice. Always consult with a healthcare professional before making any decisions related to medication or treatment.