Asthma drugs

  3 types of asthma drugs:

1) Bronchodilators
2) Leukotriene antagonists
3) Anti-inflammatory Agents



      1) Bronchodilators

1. Beta2-adrenergic receptor agonists (albuterol, , terbutaline, formoterol and salmeterol are long-acting, metoproterenol). these drugs act on beta2-adrenergic receptor causing smooth muscles relaxation; have minimal cardiac adverse effects (tachycardia, arrhytmia); most commonly they used as  inhalants; commonly cause muscle tremor.
2. Muscarinic antagonists (tiotropium - long-acting, ipratropium). They are used as inhalants; minimal cardiovascular and system side effects, very good in COPD.
3. Non-selective beta-agonists (isoproterenol, epinephrine is used in acute asthma and anaphylactic reactions)
4. Methylxantines (theophylline). Increases heart muscle contractility, blood pressure, heart rate, renal blood flow, relaxes bronchial smooth muscles, stimulate medullary respiratory center. Used in asthma, COPD, infant apnea.

     2) Leukotriene antagonists

1. Leukotriene antagonists (zafirlucast, montelucast). They block leukotriene receptors.
2. 5-Lipoxygenase inhibitors (zileuton). Blocks leukotriene synthesis.  Both good active orally, prevents exersice-induced asthma and aspirin-induced asthma.

      3) Anti-inflammatory Agents

1. Corticosteroids (beclomethasone, prednisone, prednisolone). Decrease inflammation, edema, used orally and inhaled, can be used IV in status asthmaticus.
2. Release inhibitors (cromolyn, nedocromil). Inhibit mast cell degranulation, good for prevention allergy-induced bronchoconstriction.