dofetilidi

Dofetilide is a class III antiarrhythmic medication used in adults to convert atrial fibrillation or flutter to normal sinus rhythm and to maintain sinus rhythm after successful cardioversion. It is marketed under brand names such as Tikosyn and is available as an oral capsule. The drug is selectively blocking the rapid component of the delayed rectifier potassium current (IKr) through hERG channels in cardiac tissue. By prolonging repolarization and the QT interval, dofetilide increases the refractory period and can help stabilize cardiac rhythm.

Pharmacokinetics and use in special populations: Dofetilide is predominantly eliminated by the kidneys, with minimal hepatic metabolism. Dose and duration of therapy are adjusted based on renal function (creatinine clearance) and individual QT response. In renal impairment, the drug may accumulate, requiring dose reductions or avoidance. Because of its narrow therapeutic index, initiation or dose changes are performed under careful monitoring.

Monitoring and safety: Initiation and dose adjustments require hospital-based continuous ECG monitoring for several days to observe QT interval changes and prevent torsades de pointes, a potentially life-threatening arrhythmia. Baseline and periodic assessment of the QTc interval, electrolyte levels (potassium and magnesium), and renal function are recommended, with correction of electrolyte abnormalities prior to or during treatment. Avoid concomitant use with other QT-prolonging drugs and manage potential drug interactions.

Contraindications and cautions: Dofetilide is contraindicated in congenital long QT syndrome, significant baseline QT prolongation, severe renal impairment (e.g., CrCl very low), and in patients with electrolyte disturbances that are not corrected. Caution is advised in elderly individuals and those with structural heart disease or bradycardia.