What are they
The pharmacological treatment of asthma includes substances of different types, which are chosen depending on the nature of the asthma (allergic or non-allergic) and the level of severity and persistence of the symptomatology (determined according to an international classification system that provides for 5 clinical forms).
How they work
Anti-asthmatic drugs can intervene on two fundamental pathogenetic mechanisms of the disease: bronchoconstriction and inflammation. Based on the type of action they exert, exclusively or predominantly, they can therefore be divided into two groups: bronchodilators and anti-inflammatories.
- Bronchodilators work by actively reducing the muscles of the bronchi or preventing their contraction.
- Anti-inflammatories act by blocking the activity of the various cells responsible for allergic responses and inflammatory processes (mast cells, lymphocytes, neutrophil leukocytes, eosinophil leukocytes), the production of proinflammatory molecules (histamine, prostaglandins, thromboxanes, leukotrienes) or the effects of antibodies involved in the allergic response (IgE).
What are they?
Bronchodilators include three categories of drugs:
| Category | Mechanism of action | Active ingredients |
|---|---|---|
| Adrenergic beta-2 receptor agonists | By stimulating these specific receptors present in the bronchial muscles, they cause their relaxation | Salbutamol, fenoterol, terbutaline, salmeterol, Formoterol |
| Muscarinic receptor antagonists | By binding to these specific receptors present in the bronchial muscles, they prevent their contraction | Ipratropium bromide |
| Methylxanthines | With a dual mechanism of action, they prevent the contraction of the bronchial musculature and at the same time favor the relaxation (in addition to also having an anti-inflammatory effect additional). | Theophylline, aminophylline |
Among the anti-inflammatories include the following classes of drugs:
| Class | Mechanism of action | Active ingredients |
|---|---|---|
| Corticosteroids | They interfere at various levels with inflammatory reactions; | Beclomethasone, budesonide, fluticasone, mometasone |
| Mast cell stabilizers | They block the activation of these cells, involved in the allergic response and inflammatory reactions; | Cromoglycate sodium, nedocromil |
| Antileukotrienes | They work by preventing the synthesis of leukotrienes (zileuton) or by blocking its effects (montelukast, zafirlukast); | Zileuton, montelukast, zafirlukast |
| Monoclonal antibodies | Bind to IgE | Omalizumab |
How to use them
The treatment of asthma has the dual purpose of achieving good control of the disease and resolving acute crises if necessary.
Anti-asthmatics are classified as:
- background drugs, intended to treat pathological conditions that induce asthmatic symptoms;
- symptomatic drugs, intended to counteract only the symptoms, in particular bronchoconstriction.
In this perspective, all anti-inflammatories and symptomatic drugs bronchodilators are to be considered background drugs.
Asthma therapy can use both types of drugs, both in the continuous treatment and in the resolution of exacerbations, selecting them according to the effectiveness and above all the speed of action.
In the treatment of acute crises, for example, faster effect bronchodilators (salbutamol, terbutaline, fenoterol, ipratropium bromide) and more powerful anti-inflammatories (corticosteroids) are preferred.
Basically, the preferred route of administration of antiasthmatics is inhalation, except for methylxanthines and antileukotrienes which are taken by mouth and for the omalizumab antibody which is administered subcutaneously.
The treatment of severe acute crises may require systemic administration of both corticosteroids and bronchodilators, sometimes intravenously.
Effects
Considering the most widely used drugs:
- Beta-2 agonist bronchodilators may cause tachycardia, hypotension, muscle cramps, headache;
- corticosteroids can, in prolonged use, predispose to infections, gastro-duodenal ulcer, osteoporosis, endocrine imbalances;
- Cromoglycate sodium and nedocromil are, on the other hand, quite well tolerated.
Joycelyn Elders is the author and creator of EmpowerEssence, a health and wellness blog. Elders is a respected public health advocate and pediatrician dedicated to promoting general health and well-being.
The blog covers a wide range of topics related to health and wellness, with articles organized into several categories.