What is a contraindication for initiating Dofetilide (Tikosyn)?

The contraindication for initiating Dofetilide (Tikosyn) is a baseline QTc interval greater than 440 milliseconds. Dofetilide is a class III antiarrhythmic medication that can prolong the QT interval, which increases the risk of Torsades de Pointes, a potentially life-threatening form of ventricular tachycardia. Therefore, patients with an existing prolonged QTc interval are at a significantly higher risk for serious arrhythmic events when treated with this medication. Clinicians must assess the QTc interval before starting treatment to ensure the safety of the patient.

Other factors such as age over 60, a previous history of heart failure, or reported allergies to antibiotics do not represent direct contraindications for the initiation of Dofetilide. While they may influence the overall treatment plan or require careful monitoring, they do not carry the same immediate risk of arrhythmogenesis that a baseline QTc > 440 msec does.