Dofetilide

Definition

Dofetilide is a Class III antiarrhythmic drug that works by blocking potassium channels, thereby prolonging the action potential and refractory period in cardiac cells. It is primarily used to treat atrial fibrillation and atrial flutter.

5 Must Know Facts For Your Next Test

1. Dofetilide selectively blocks the IKr (rapid component of the delayed rectifier potassium current) in cardiac cells.
2. It is administered orally and requires hospitalization for initiation due to the risk of serious arrhythmias.
3. Dosage must be adjusted based on renal function, specifically creatinine clearance.
4. The primary adverse effect is QT interval prolongation, which can lead to Torsades de Pointes.
5. Monitoring of ECG and electrolytes is essential during treatment with dofetilide.

Review Questions

• What specific potassium current does dofetilide block in cardiac cells?
• Why must dofetilide therapy be initiated in a hospital setting?
• What major adverse effect should be closely monitored while a patient is on dofetilide?

Related terms

Atrial Fibrillation: A common type of arrhythmia characterized by rapid and irregular beating of the atria.

QT Interval: A measurement on an ECG representing the time it takes for ventricular depolarization and repolarization.

Torsades de Pointes: A specific type of abnormal heart rhythm that can be potentially life-threatening and is associated with prolonged QT interval.