Treatment of Cough in Clinical Practice: Which Preparations Are Suitable and When?

Classification of Cough

Based on duration, cough is classified as acute (lasting no more than 3 weeks), prolonged (with intermittent duration of 3–8 weeks), and chronic, if it persists longer than 8 weeks. Every patient with chronic cough should be examined by a doctor. Further classification is based on the nature of the cough:

1. Dry, irritating, with potential to progress to barking or hoarse – for its treatment we use centrally or peripherally acting antitussive agents.
2. Paroxysmal, occurring at night or after exertion, often seen in bronchial asthma – here, inhaled bronchodilators or anti-inflammatory drugs provide relief.
3. Moist, productive, with expectoration of mucus, typically appearing in the later stages of respiratory infections – mucoregulatory drugs are suitable for its treatment.

Choice of Therapy

Antitussive Agents

For the treatment of non-productive cough, antitussive agents are recommended. These include codeine, a central antitussive, which quickly suppresses the cough center and has an analgesic effect. Codeine is metabolized by cytochrome P450. Its side effects include respiratory depression, drowsiness, constipation, and summation of sedative effects. Dextromethorphan, a codeine-based antitussive with a similar spectrum of effects, excluding the analgesic effect, is also metabolized by cytochrome P450 and is only available by prescription. Codeine antitussive agents are reserved for situations where it is also necessary to influence pain, e.g., in bronchogenic carcinoma. 

Butamirate is a non-codeine central antitussive with predominantly central anticholinergic and bronchospasmolytic effects. Its side effects include drowsiness, nausea, and urticaria. Dropropizine can also be used, which blocks sensitive perceptive sites in the laryngotracheal area through a peripheral mechanism. It may act antagonistically on histamine receptors, causing side effects similar to those associated with butamirate use.

The levorotatory isomer of dropropizine, levodropropizine, exhibits significantly fewer side effects and sedative effects than the racemic form. It also has antiallergic and antibronchospastic effects, does not suppress respiratory functions or mucociliary clearance, and is indicated for all bronchial and lung diseases accompanied by dry cough. It can be administered before a bronchoscopy examination. It shows no interactions with β₂-agonists, methylxanthines, corticosteroids, antibiotics, mucoregulators, or antihistamines.

Mucoregulatory Agents, Mucokinetics, and Expectorants

Medicines for the treatment of moist productive cough are divided into mucoregulatory agents that normalize the composition and volume of bronchial secretions (carbocisteine, erdosteine), mucolytics that reduce viscosity of mucus and increase mucociliary clearance (ambroxol, bromhexine, erdosteine, N-acetylcysteine), mucokinetics that enhance mucus mobility and its removal (ambroxol, bronchodilators, surfactant), and finally, expectorants that increase production of thin mucus through vagal and osmotic mechanisms (guaifenesin, saline expectorants, emetine).

Available active substances include bromhexine and ambroxol, which have a secretomotor effect, increase mucus production, reduce mucus adhesion to respiratory tracts, and enhance antibiotic penetration into lung tissue. Their side effects include GIT mucosal irritation and ulcer disease activation.

Guaifenesin can also be used, acting as an expectorant, anxiolytic, and central muscle relaxant. Its central effects lead to the summation of sedative effects and depression, and it may cause vomiting, rash, and enhanced effects of substances with depressive effects on the CNS. Ulcer disease is a contraindication. 

Carbocisteine increases the production of thin bronchial mucus. Its side effects include headaches, bronchospasm, and hypersensitivity. N-acetylcysteine increases the production of thin bronchial mucus and can be used as an antidote in paracetamol poisoning, however, it reduces the efficacy of some antibiotics and its side effects include nausea, vomiting, hypersensitivity, urticaria, and bronchospasm. Ulcer disease is a contraindication.

Erdosteine, which reduces bacterial adhesion to respiratory tract mucosa and acts synergistically with antibiotic therapy, cannot be overlooked. It reduces the elasticity and viscosity of mucus, normalizes its volume, does not lead to mucus hypersecretion, and due to its antiflogistic effect, it alleviates manifestations of bronchial inflammation. Side effects include pyrosis, nausea, and hypersensitivity reactions. As the only mucolytic, it has insurance coverage for COPD indication when prescribed by a pulmonologist. Without insurance coverage, it may be prescribed by any specialist with designation P – the patient pays.

For the administration of phytopharmaceuticals in the treatment of productive cough (from plantain, marshmallow, mallow, thyme, wild thyme, mint, anise, primrose, ivy, soapwort, and licorice), there is not enough evidence, and their use is based only on experience.

Summary for Practice

For treating dry irritating cough, we choose a non-opioid peripheral antitussive that does not suppress the respiratory center and does not cause undesirable sedation. For treating moist cough, we select a mucolytic agent with a good safety profile, supporting mucociliary function without stimulating mucus hypersecretion. When choosing, we consider other individual patient needs and factors such as sedation, route of administration, potentiation of antibiotic effects, or anti-inflammatory effects. Combining antitussive and expectorant in one dose is irrational.

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Source: Kos S. Modern treatment and differential diagnosis of cough. Medicine for Practice 2020; 17 (1): 18–22.