Medical Pharmacology Practice Questions: Antiarrhythmic Drugs

Dofetilide belongs to which class of antiarrhythmic drugs?
1. Class 1
2. Class 2
3. Class 3
4. Class 4
Choose the correct statement(s) concerning the pharmacology of dofetilide.
1. Dofetilide is classified as a pure IKr antagonist.
2. Dofetilide administration shortens both atrial and ventricular action potentials.
3. On the ECG, dofetilide administration is associated with an increase in PR and QRS duration.
4. All of the above
Dofetilide exhibits excellent bioavailability (about 92%).
1. True
2. False
Concerning dofetilide pharmacokinetics and dosing, choose the correct statement(s).
1. Most of the drug (about 75%) is excreted by the kidney, suggesting the need to adjust doses according to creatinine clearance values.
2. About 25% of dofetilide is subject to cytochrome P450 metabolism, involving mainly the CYP3A4 isoform.
3. Agents inhibiting this CYP3A4 isoform (e.g. verapamil) may result in higher serum dofetilide levels.
4. A & B
5. A, B & C
Choose the correct statement(s) concerning clinical usage and clinical characteristics of dofetilide.
1. Dofetilide is a negative inotropic drug, therefore depressing ventricular contractility.
2. Dofetilide is useful in treating atrial fibrillation.
3. Dofetilide is useful in treating atrial flutter.
4. A & B
5. A & C
6. B & C
7. A, B & C
Dofetilide may be effective and safely used for atrial fibrillation conversion and recurrence prevention even in patients with congestive heart failure.
1. True
2. False
Choose the correct statement(s) concerning dofetilide adverse effects
1. .Dofetilide administration is associated with about a 3%-4% incidence of torsades de pointes.
2. Dofetilide probably should be avoided in those patients showing substantial renal dysfunction.
3. Dofetilide administration should be avoided in patients exhibiting a baseline QT prolongation.
4. All of the above
Dronedarone exhibit similar electrophysiological properties as this agent:
1. Ibutilide
2. Esmolol
3. Amiodarone
4. Diltiazem
Dronedarone has been approved for treatment of which one(s) of the following arrhythmias?
1. Atrial fibrillation
2. Atrial flutter
3. Both
4. Neither
Following oral administration, bioavailability of Dronedarone is about 15%-20%. Which one(s) of the following additional Dronedarone characteristics is/are correct?
1. Dronedarone exhibits extensive first-pass hepatic metabolism.
2. Dronedarone clearance is mainly nonrenal.
3. Both
4. Neither
Dronedarone administration should probably be avoided in patients exhibiting advanced CHF.
1. True
2. False