Last reviewed 2026-04-20 · How we verify

Tikosyn (Dofetilide)

Blocks cardiac potassium channel IKr to prolong repolarization and delay arrhythmia recurrence.

Dofetilide (Tikosyn) is a selective Class III antiarrhythmic that blocks the IKr potassium channel to maintain normal sinus rhythm and convert atrial fibrillation/flutter. The drug demonstrates strong efficacy with >90% bioavailability and a 10-hour half-life, enabling convenient twice-daily dosing. Major safety concerns include dose-dependent torsade de pointes (0.8% in supraventricular arrhythmia patients, 3.3% in CHF patients) and numerous drug interactions via renal cation transport inhibition, requiring careful patient selection and baseline QT assessment. Dofetilide remains indicated for highly symptomatic AF/AFl patients despite life-threatening arrhythmia risks, with strict contraindications for long QT syndrome and severe renal impairment.

At a glance

Mechanism of action

Dofetilide is a Class III antiarrhythmic agent that selectively blocks the IKr potassium channel, which carries the rapid component of the delayed rectifier potassium current in cardiac tissue. At clinically relevant concentrations, dofetilide demonstrates selective blockade of IKr with no significant effects on other repolarizing potassium currents (IKs, IK1), sodium channels, or adrenergic receptors. This selective mechanism prolongs the cardiac action potential duration and refractory period, thereby delaying the recurrence of atrial fibrillation and atrial flutter in patients who have been converted to normal sinus rhythm.

Approved indications

• Maintenance of Normal Sinus Rhythm (Delay in AF/AFl Recurrence)
• Conversion of Atrial Fibrillation/Flutter

Boxed warnings

• To minimize the risk of induced arrhythmia, patients initiated or re-initiated on TIKOSYN should be placed for a minimum of 3 days in a facility that can provide calculations of creatinine clearance, continuous electrocardiographic monitoring, and cardiac resuscitation. For detailed instructions regarding dose selection, see DOSAGE AND ADMINISTRATION .

Common side effects

• Headache
• Chest pain
• Dizziness
• Dyspnea
• Accidental injury
• Flu syndrome
• Ventricular tachycardia

Serious adverse events

• Torsade de Pointes (CHF patients)
• Torsade de Pointes (supraventricular arrhythmias)
• Torsade de Pointes (MI patients)

Drug interactions

• Verapamil
• Cimetidine
• Trimethoprim (alone or with sulfamethoxazole)
• Ketoconazole
• Prochlorperazine
• Dolutegravir
• Megestrol
• Hydrochlorothiazide (alone or in combinations such as with triamterene)

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Tikosyn CI brief — competitive landscape report
• Tikosyn updates RSS · CI watch RSS
• Pfizer Inc. portfolio CI