The respiratory system facilitates the exchange of oxygen and carbon dioxide by the processes of inspiration and expiration. It is composed of the upper and lower respiratory tracts, such as the lungs, trachea, nose, and bronchi. Asthma is a common respiratory disease caused by an abnormal allergic response that leads to inflammation and narrowing of the airways. There are many classes of medications used to treat asthma, some of which are used as rescue medications, while others are used to prevent and decrease the severity of attacks. Chronic obstructive pulmonary disease, or COPD, includes chronic bronchitis and emphysema, which cause long-term breathing issues. Acute infection of the lung tissues is called pneumonia. It is treated with antimicrobials tailored to the causative microorganism.
Table showing common drug classes and examples of the respiratory system
| Drug class | Generic name | Brand name(s) | Primary use |
| Beta 2 agonists | Albuterol, salmeterol | Ventolin, Serevent Diskus | Asthma, COPD |
| Inhaled Corticosteroids | Budesonide, fluticasone | Pulmicort Flexhaler, Flovent HFA | Asthma, COPD |
| Anticholinergics or muscarinic antagonists | Ipratropium, tiotropium | Atrovent, Spiriva Respimat | COPD |
| Leukotriene modifiers | Montelukast, zafirlukast | Singulair, Accolate | Asthma, allergies |
| Antihistamines | Diphenhydramine, cetirizine, loratidine | Benadryl, Zyrtec, Claritin | Allergies |
| Antitussives | Benzonatate, dextromethorphan | Tessalon, Delsym | Treatment of cough |
| Decongestants | Phenylephrine, pseudoephedrine | Sudafed | Treatment of nasal congestion |