A 25 year old woman with a history of asthma complains of worsening asthma attacks. Before, she had symptoms less than twice a week with less than two night attacks a month. These symptoms were easily controlled with her albuterol inhaler. Now, she is symptomatic every day of the week with frequent weekly night attacks. The albuterol inhaler helps control the acute attack, but she is concerned that she needs additional medication. You decide to add low-dose inhaled steroids and a long-acting bronchodilator. Which of the following drugs would be the most appropriate long-acting bronchodilator to add?
A.Salmeterol
B.Cromolyn
C.Theophylline
D.Zafirlukast
E.Salmeterol or Theophylline
Explanation
Salmeterol (choice A) and Theophylline (choice C) are the only two drugs listed that are considered long-acting bronchodilators. Salmeterol is a long-acting beta-2 agonist that acts as a bronchodilator by increasing cAMP in smooth muscle cells throughout the respiratory system resulting in muscle relaxation. Theophylline is a methylxanthine that also causes smooth muscle relaxation by increasing levels of cAMP. Between the two, salmeterol would be preferred because theophylline has a narrow therapeutic index with risk of cardiotoxicity and neurotoxicity; therefore choice E is incorrect.
Cromolyn (choice B) prevents the release of mediators from mast cells and is therefore not a bronchodilator.
Zafirlukast (choice D) is an antileukotriene that inhibits leukotriene receptors to mediate the inflammatory response and is therefore not a bronchodilator.