Question 281

Question:

A 68 year old woman is diagnosed with mild hypertension and her physician elects to start treatment with a beta-blocker. The patient has a medical history significant for asthma for which she takes an albuterol inhaler as necessary, though she has not used it in three years. Which beta blocker is least likely to cause an exacerbation of her asthma?

Correct Answer: B.  Atenolol

Atenolol is the only beta-1 selective beta-blocker. Other beta-1 selective beta-blockers include metoprolol, esmolol, and bisoprolol. All the other beta-blockers listed are nonselective (they block both beta-1 and beta-2).

In the lungs, the beta-2 receptor helps to mediate against bronchoconstriction (smooth muscle). This explains the use of beta-2 agonists such as albuterol and salmeterol in the treatment of reactive airway diseases such as asthma. Blocking this receptor may lead to a worsening of respiratory symptoms. Thus, most clinicians will recommend the use of a beta-1 selective agent when treating a patient with a history of lung disease (e.g. asthma, COPD, emphysema).