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Propranolol, because it is a non-selective ß-blocker
18%
52/295
Metoprolol, because it is a selective ß1 > ß2 blocker
64%
189/295
Atenolol, because it is a selective ß2 > ß1 blocker
5%
16/295
Labetalol, because it is a selective ß1 > ß2 blocker
15/295
Nadolol, because it is a selective ß1 > ß2 blocker
1%
2/295
Select Answer to see Preferred Response
Because the patient has a history of COPD, he should be treated with a selective ß1 blocker such as metoprolol or atenolol. When using a ß-blocker to treat a patient with hypertension, tachycardia, acute MI, history of MI, or arrhythmia, it is important to tailor pharmacotherapy to the patient's comorbidities based on the drugs' selectivity. Non-selective ß1 and ß2 antagonists (propanolol, nadolol, and timolol) should be avoided in patients with asthma and COPD because of the risk of bronchoconstriction caused by ß2 blockade. Selective ß1 blockers (metoprolol, atenolol, betaxolol, and esmolol) decrease heart rate and contractility by their ß1 effect without causing marked bronchoconstriction secondary to ß2 cross-reactivity. Nonselective a- and ß-antagonists (labetalol and carvedilol) are primarily used in heart failure and have similar risks for patients with COPD and asthma as non-selective ß-blockers. In a summary of the American College of Cardiology and American Heart Association guidelines for the management of acute MI, Campbell-Scherer and Green review the role of ß-blockers in improving mortality. In the review the authors list absolute contraindications to ß-blocker therapy for acute MI: evidence of low output state; increased risk of cardiogenic shock; and signs of heart failure because ß-blocker therapy increases mortality in these patients. In an editorial, Rutten and Groenwold review the benefits of ß-blocker therapy for acute and subacute myocardial infarction. They emphasize that even for patients with COPD, ß-blocker therapy is associated with a 0.59 mortality hazard ratio. Illustration A shows the mechanism of adrenergic blockade. Incorrect Answers: Answers 1 and 5: Propranolol and nadolol are non-selective ß-blockers, which could theoretically exacerbate COPD in this patient; a selective ß1 is a better choice in this patient. Answer 3: Atenolol is a selective ß1 > ß2 blocker. Answer 4: Labetalol is a non-selective adrenergic blocker with the affinity to ß1 = ß2 = a1 > a2.
4.2
(9)
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