| Drug | Mechanism of action | Adverse effects |
| Beta 2 agonists: albuterol, terbutaline, salmeterol, formoterol | Relax bronchiolar smooth muscle by stimulating bronchodilating beta 2 receptors → activation of adenylate cyclase → increased cAMP. Salmeterol and formoterol have greater specificity for beta 2 receptors. | Tremors, tachycardia, tolerance, cramps; salmeterol can increase the risk of severe asthma attacks and death. |
| Corticosteroids (budesonide, beclomethasone, fluticasone, triamcinolone, prednisone, methylprednisone, prednisolone) | Anti-inflammatory: reduce secretions and mucosal inflammation, decreasing the severity and frequency of asthma attacks. | Oral candidiasis, cough, adrenal suppression, osteoporosis, growth suppression, peptic ulcers, myopathy, hypertension, Cushing’s syndrome. |
| Methylxanthines (theophylline) | Inhibit phosphodiesterase, preventing cAMP breakdown → increased cAMP and cGMP levels → bronchodilation. Also decrease release of inflammatory mediators from mast cells; adenosine receptor antagonist. | Narrow therapeutic index, tachycardia, arrhythmias, sudden death, CNS excitation, nervousness, insomnia, tremors, seizures, gastric upset. |
| Cromolyn, nedocromil | Inhibit release of inflammatory mediators from mast cells and suppress leukocyte chemotaxis. Used to prevent asthma, including exercise- and allergen-induced bronchoconstriction. | Cough, unpleasant taste, dermatitis, myositis; generally well tolerated. |
| Zileuton | Inhibits 5-lipoxygenase, an enzyme required for leukotriene synthesis. | Headache, nausea, gastric upset, myalgia, Churg Strauss syndrome. |
| Leukotriene modifiers (montelukast, zafirlukast) | Block leukotriene receptors in the airways, antagonizing leukotriene effects. Also effective in aspirin induced asthma. | Headache, nausea, gastric upset, myalgia, Churg Strauss syndrome, elevation of liver enzymes. |
| Muscarinic antagonists (ipratropium, tiotropium) | Block muscarinic receptors in the airways, decreasing bronchoconstriction and mucosal secretion. | Anticholinergic effects (especially in elderly), cough, dry mouth, throat irritation, urinary retention, tachycardia, delirium, blurred vision. |
| Monoclonal antibodies (omalizumab) | Humanized recombinant monoclonal antibody to IgE that blocks IgE binding to mast cells, preventing degranulation. | Injection site reactions, risk of malignancies, rarely anaphylaxis, high cost. |
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