A 67-year-old man with atrial fibrillation presents with heart rate 52 bpm, blood pressure 98/62 mmHg, and respiratory rate 16/min. He takes digoxin and metoprolol. Recent serum digoxin level is 2.1 ng/mL (therapeutic range 0.8–2.0). He reports nausea and blurred vision but denies palpitations. EKG shows prolonged PR interval without heart block. His physician recognizes these symptoms reflect digoxin toxicity. Which pharmacologic property necessitates close monitoring of serum digoxin concentrations in patients receiving concurrent beta-blockers?
- A)High volume of distribution
- B)Zero order metabolism at baseline doses
- C)Low potency
- D)Low therapeutic indexGABARITO
- E)High efficacy
Explicação
Drugs such as digoxin have a low therapeutic index, meaning the toxic dose is close to the effective dose. Because the therapeutic window is narrow, modest increases in serum concentration can produce toxicity, so monitoring is often required. Ver explicação completa e trilha adaptativa →