Pharmacology and Drug Therapy Flashcards

Why does dofetilide require mandatory 3-day in-hospital initiation?

Answer: Risk of QT prolongation and torsades de pointes

Dofetilide causes dose-dependent QT prolongation and can precipitate torsades de pointes, requiring in-hospital QTc and renal monitoring during initiation.

Which antiarrhythmic drug requires regular monitoring of thyroid and pulmonary function due to its molecular structure?

Answer: Amiodarone

Amiodarone contains two iodine atoms and can cause thyroid dysfunction and pulmonary toxicity requiring periodic thyroid function tests and chest imaging.

Sotalol combines the pharmacological actions of which two Vaughan Williams classes?

Answer: Class II and Class III

Sotalol combines Class II (beta-blocking) and Class III (potassium channel blocking) actions, reducing heart rate and prolonging repolarization.

Ranolazine's antiarrhythmic properties are primarily due to inhibition of which sodium current?

Answer: Late INa

Ranolazine inhibits the late (persistent) sodium current, reducing intracellular sodium and calcium overload that can trigger arrhythmias.

Which drug should be avoided in Wolff-Parkinson-White syndrome with atrial fibrillation because it enhances accessory pathway conduction?

Answer: Digoxin

Digoxin can enhance conduction through the accessory pathway in WPW, potentially precipitating ventricular fibrillation during atrial fibrillation.

How does dronedarone structurally differ from amiodarone?

Answer: It is non-iodinated

Dronedarone is a non-iodinated benzofuran derivative developed to retain antiarrhythmic efficacy while eliminating iodine-related thyroid and pulmonary toxicity.