Last reviewed 2026-04-20 · How we verify

Tikosyn (DOFETILIDE)

Tikosyn works by blocking the potassium channels in the heart, which helps to regulate the heart's rhythm.

Tikosyn (DOFETILIDE) is a small molecule antiarrhythmic medication developed by Pfizer, targeting the potassium voltage-gated channel subfamily H member 2. It is used to treat atrial fibrillation, cardioversion of atrial fibrillation, and cardioversion of atrial flutter. Tikosyn is off-patent, with 13 generic manufacturers available. Key safety considerations include the risk of torsades de pointes, a potentially life-threatening heart rhythm disorder. As an off-patent medication, its commercial status is largely driven by generic competition.

At a glance

Mechanism of action

Mechanism of Action. TIKOSYN (dofetilide) shows Vaughan Williams Class III antiarrhythmic activity. The mechanism of action is blockade of the cardiac ion channel carrying the rapid component of the delayed rectifier potassium current, IKr. At concentrations covering several orders of magnitude, dofetilide blocks only IKr with no relevant block of the other repolarizing potassium currents (e.g., IKs, IK1). At clinically relevant concentrations, dofetilide has no effect on sodium channels (associated with Class effect), adrenergic alpha-receptors, or adrenergic beta-receptors.

Approved indications

• Atrial fibrillation
• Cardioversion of Atrial Fibrillation
• Cardioversion of Atrial 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

• Ventricular arrhythmias
• Ventricular tachycardia
• Ventricular fibrillation
• Torsade de Pointes
• AV block
• Bundle branch block
• Heart block
• Headache
• Chest pain
• Dizziness
• Respiratory tract infection
• Dyspnea

Drug interactions

• High Risk QT Prolonging Agents
• amiloride
• artemether
• asenapine
• bepridil
• bretylium
• chloroquine
• ciprofloxacin
• cisapride
• dextropropoxyphene
• disopyramide
• dolasetron

Key clinical trials

• The PIVATAL Study -Study of Ventricular Arrhythmia (VTA) Ablation in Left Ventricular Assist Device (LVAD) Patients (PHASE4)
• Pulsed Field Ablation (PFA) vs Anti-Arrhythmic Drug (AAD) Therapy as a First Line Treatment for Persistent Atrial Fibrillation (NA)
• Assessing the Neurological Outcomes After Atrial Fibrillation Ablation for Rhythm Control
• Study of LQT-1213 on QTc-induced Prolongation in Healthy Adult Subjects (Part1) and on Congenital Long QT in Patients Diagnosed With Type 2 or 3 Long QT Syndrome (Part 2). (PHASE1,PHASE2)
• A Comparison of Antiarrhythmic Drug Therapy and Radio Frequency Catheter Ablation in Patients With Paroxysmal Atrial Fibrillation (PHASE4)
• First Line Radiofrequency Ablation Versus Antiarrhythmic Drugs for Persistent Atrial Fibrillation Treatment (RAAFT-3) (PHASE3)
• Genetics of QT Prolongation With Antiarrhythmics
• Catheter Ablation vs Anti-arrhythmic Drug Therapy for Atrial Fibrillation Trial (NA)

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

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 portfolio CI