Summary Drugs Acting on the Respiratory System

Drugs Acting on the Respiratory System Drugs that act on the respiratory system include • Bronchodilators • Corticosteroids • Cromoglycates • Leukotriene receptor antagon • Antihistamines • Cough preparations • Nasal decongestants Asthma is a chronic inflammatory disorder of the airways causes recurrent episodes of wheezing, breathlessness, chest tightness, and coughing, particularly at night or in the early morning associated with airflow obstruction that is often reversible either spontaneously or with treatment. Bronchodilators Drugs used to relieve bronchospasms associated with respiratory disorders Includes: 1-Adrenoceptor agonists: - Selective β2-agonists - Other adrenoceptor agonists 2-Antimuscarinic bronchodilators 3-Xanthine derivatives Adrenoceptor agonists (i) Selective beta2 agonists Stimulate beta2 receptors in smooth muscle of the lung, promoting bronchodilation, and thereby relieving bronchospasms They are divided into short-acting & long acting types Short-acting β-2 agonists Salbutamol Terbutaline Long-acting β-2 agonists Formoterol Salmeterol Adverse effects Tachycardia Palpitations Headache Tremor (ii) Other adrenoceptor agonists Less suitable & less safe for use as bronchodilators because they are more likely to cause arrhythmias other side effects: Ephedrine Adrenaline (epinephrine) injection