Bronchodilator
A bronchodilator (or broncholytic , bronchospasmolytic ) is a medicine that lowers the tone of the bronchial muscles and thus causes the bronchi to widen . Bronchodilators are typically used to treat bronchial asthma and COPD .
Bronchodilation
Bronchodilation refers to the expansion of narrowed bronchi (relaxation of the bronchial muscles).
Activation of the sympathetic system increases adrenaline and catecholamine levels in the blood and this leads to an expansion of the airways in the lungs. Drug bronchodilation can occur in different ways. In medicine, beta sympathomimetics, parasympatholytics and theophyllines are used to dilate the bronchi. Also, stimulants ( doping ) as amphetamines , ephedrine or caffeine act in the same direction. An indirect bronchodilator is cortisone spray. It reduces the inflammatory swelling of the bronchi and thus helps with bronchodilation. The drugs that cause bronchodilation have side effects in higher doses, such as on the cardiovascular system.
Mechanism of action
β 2 receptor → heterotrimeric G s protein → adenylate cyclase → cAMP ↑ → protein kinase A → phosphorylation of (Ca 2+ ) 4 - calmodulin → inhibition (reduced binding and activation) of myosin light chain kinase .
Bronchodilation leads to improved oxygen uptake and easier removal of mucus.
Drug groups
Pharmacologically , bronchodilators are divided into three groups of active substances:
β-adrenoceptor agonists
The stimulation of the β 2 adrenoceptor by β 2 sympathomimetics leads to relaxation of the bronchial muscles and triggers a broncho spasm . Representatives of this group of substances are, for example, salbutamol , salmeterol , terbutaline , fenoterol , reproterol , clenbuterol or formoterol .
Theophylline
Theophylline is a xanthine derivative whose mechanism of action is not yet fully understood. On the one hand, it inhibits the enzyme phosphodiesterase in high doses , which increases the concentration of the second messenger cAMP in the bronchial muscle cells . On the other hand, theophylline blocks the adenosine receptors , which otherwise narrow the bronchi and cause the release of histamine .
Muscarinic receptor antagonists
Parasympatholytics (anticholinergics) prevent the binding of the neurotransmitter acetylcholine to the muscarinic acetylcholine receptor . Ipratropium bromide is short- acting , tiotropium bromide , glycopyrronium bromide , aclidinium bromide and umeclidinium bromide are long- acting.
literature
- Ernst Mutschler u. a .: drug effects . 8th edition. Scientific publishing company. Stuttgart 2001. ISBN 3-8047-1763-2
