Introduction
Since COPD (Chronic Obstructive Pulmonary Disease) is an inflammatory degenerative disease in which, among other things, certain parts of the airways, the bronchi, swell up, two types of medication are used to treat it. On the one hand, so-called bronchodilators are used. This is a group of drugs that use the body’s own signaling pathways to cause the bronchi to dilate, thereby reducing airway resistance and making it easier to breathe.
On the other hand, from a certain extent of the disease onwards, cortisone is also used, a substance that is produced naturally in the body and has a strong anti-inflammatory effect, thus alleviating the symptoms. Since cortisone can have many side effects with regular use and makes the patient susceptible to infections, the step-by-step therapy for COPD begins with combinations of bronchodilators. All these drugs are usually given locally, i.e. they act directly on the lungs. These include, for example, powders that are atomized and inhaled or liquids that are also inhaled.
Brochodilators
Bronchodilators are drugs that dilate the bronchi, i.e. the larger air-conducting airways. In certain situations, especially during sporting activities, the body wants to widen the airways and thus make breathing easier. After exertion and at rest, the airways are then narrowed again.
For this purpose, the body uses certain messenger substances and signal paths. Bronchodilators make use of these mechanisms by imitating the dilating (=dispersing) messenger and signal substances or by blocking the constricting substances. In a COPD patient, the airways are constantly narrowed, partly by mucus, but also by inflammatory swelling.
Bronchodilators facilitate breathing, which can lead to a great improvement of the symptoms. This topic might also be of interest to you: Therapy of COPD body functions that we humans cannot consciously control, such as digestion or the speed of the heartbeat, are controlled by the so-called autonomic nervous system, which can be divided into two antagonists: the sympathetic and parasympathetic nervous systems. While the parasympathetic nervous system tends to promote processes that help the body recover, the sympathetic nervous system promotes processes that make the body capable of fighting or escaping: It makes the heart beat faster, tenses muscles and mobilizes power reserves, reduces irrelevant functions such as digestion and expands the bronchi.
This principle is used by drugs from the group of beta-2 sympathomimetics. They act on the bronchial tubes via the same signaling pathway as the messenger substance of the sympathetic nervous system (norepinephrine or adrenaline) and thus lead to a widening of the bronchial tubes. It is easy to deduce that an overdose of such a drug can then also lead to side effects such as heart palpitations, sweating and nervousness.
More articles about drugs of the group beta-2 sympathomimetics: Salbutamol spray and Viani ®Anticholinergics follow a similar principle of action as the beta-2 sympathomimetics described above. They also dilate the bronchi, but not by imitating the sympathetic nervous system (see above), but by inhibiting its antagonist, the parasympathetic nervous system. The messenger substance of the parasympathetic nervous system is acetylcholine, which causes a constriction of the bronchial tubes.
An antiCHOLINergic therefore inhibits this mechanism and prevents the bronchi from constricting. An overdose can lead to a dry mouth, for example, because salivation, which is usually encouraged by the parasympathetic nervous system, is then also inhibited. Since beta-2 sympathomimetics and anticholinergics target a similar but not the same signaling pathway, they can be used together, which means that they have a mutually reinforcing (synergistic) effect.
Phosphodiesterase 4 is an enzyme in many cells (especially in immune cells) that cleaves the signaling substance cAMP and thus promotes inflammatory reactions. If this enzyme is inhibited, the signal substance cAMP remains longer and the inflammation is not promoted. As with cortisone, this reduces the production of mucus and the swelling of the mucous membranes in the bronchi.
Studies have shown that PDE4 inhibitors in combination with other standard drugs used in COPD stage therapy bring about a significant improvement in symptoms.Furthermore, the drug is very well tolerated and only in rare cases has side effects. Theophylline is a drug that can relieve the symptoms of COPD in several ways. Firstly, it inhibits phosphodiesterases and thus acts via the mechanism described under “PDE-4 inhibitors”.
On the other hand, it also blocks a receptor found on the cells of the bronchial tubes and thus leads to a widening of the bronchial tubes. In addition, it promotes the beat of the cilia in the bronchi, which remove the mucus. However, since theophylline can easily be overdosed (small “therapeutic range”) and studies have shown that the risk of dying from cardiovascular disease is increased, theophylline is now only used as a reserve drug in difficult-to-treat COPD cases.
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