A 67-year-old man with heart failure and atrial fibrillation on digoxin 0.25 mg daily and furosemide presents with nausea, palpitations, and visual halos. Vital signs: BP 128/76 mmHg, HR 102 bpm with irregular rhythm, RR 18, Temp 37°C, SpO2 98%. Serum potassium is 3.0 mEq/L; digoxin level is 2.8 ng/mL (therapeutic: 0.5-2.0). Troponin is normal. Which mechanism explains this drug toxicity?
- A)Hypokalemia competitively blocks digoxin cardiac receptors
- B)Hypokalemia increases hepatic metabolism of digoxin
- C)Hypokalemia increases Na-K-ATPase inhibition by digoxinGABARITO
- D)Hypokalemia decreases digoxin protein binding
- E)Hypokalemia increases renal clearance of digoxin
Explicação
Digoxin works by inhibiting the Na-K-ATPase pump. Hypokalemia decreases the pump's activity, reducing intracellular potassium. This makes the Na-K-ATPase more susceptible to digoxin inhibition, amplifying digoxin's effects and causing toxicity at therapeutic d... Ver explicação completa e trilha adaptativa →