Drugs acting on the respiratory system

Drugs used in the treatment of asthma

Drug	Mechanism of action	Adverse effects
Beta 2 agonists: albuterol, terbutaline, salmeterol, formoterol	Relaxation of smooth muscle in the bronchi by stimulating bronchodilating beta 2 receptors, activation of adenylate cyclase, increased cAMP; Salmeterol and formoterol show 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, decrease the severity and frequency of asthma attacks	Oral candidiasis, cough, adrenal suppression, osteoporosis, growth suppression, peptic ulcers, myopathy, hypertension, Cushing’s syndrome
Methylxanthines (theophylline)	Inhibits phosphodiesterase hence prevents the breakdown of cAMP, increases cAMP and cGMPlevels, bronchodilation, decreased 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, suppression of leukocyte chemotaxis; Used to prevent asthma, prevent exercise and allergen induced bronchoconstriction	Cough, unpleasant taste, dermatitis, myositis, generally well tolerated
Zileuton	It inhibits the enzyme 5 lipoxygenase that is used in the synthesis of leukotrienes	Headache, nausea, gastric upset, myalgia, Churg Strauss syndrome
Leukotriene modifiers (montelukast, zafirlukast)	Antagonize the action of leukotriene on the airways by blocking leukotriene receptors; Effective in aspirin induced asthma also	Headache, nausea, gastric upset, myalgia, Churg Strauss syndrome, elevation of liver enzymes
Muscarinic antagonists (ipratropium, tiotropium)	Block muscarinic receptors in the airways, decrease bronchoconstriction and mucosal secretion	Anticholinergic effects especially in elderly, cough, dry mouth, throat irritation, urinary retention, tachycardia, delirium, blurred vision
Monoclonal antibodies (omalizumab)	It is a humanized recombinant monoclonal antibody to IgE that blocks the binding of IgE to mast cells, preventing degranulation	Injection site reactions, risk of malignancies, rarely anaphylaxis, high cost

Sign up for free to take 1 quiz question on this topic