TheraRadar
Data updated: May 26, 2026

TIKOSYN (dofetilide)

Trial Activity: Declining
Cardiovascular Approved 1999-10-01

Tikosyn (dofetilide) is a Class III antiarrhythmic indicated for the conversion of atrial fibrillation (AF) and atrial flutter (AFl) to normal sinus rhythm (NSR), as well as the maintenance of NSR in patients whose arrhythmia has lasted longer than one week. Due to the risk of inducing life-threatening ventricular arrhythmias, Tikosyn is reserved for patients who are highly symptomatic. It has not been shown to be effective in patients with paroxysmal atrial fibrillation.

Source: FDA Label • Pfizer • Antiarrhythmic

How TIKOSYN Works

Dofetilide is a Vaughan Williams Class III antiarrhythmic that selectively blocks the cardiac ion channel carrying the rapid component of the delayed rectifier potassium current ($I_{Kr}$). At clinically relevant concentrations, it does not affect other repolarizing potassium currents (such as $I_{Ks}$ or $I_{K1}$), sodium channels, or alpha/beta-adrenergic receptors. This selective blockade prolongs the action potential duration and effective refractory period, facilitating the conversion and maintenance of normal sinus rhythm.

Development Insights

Food and Drug Administration (FDA) conducting 2 trials (67%)
5 indications explored (Moderate)
drug-induced surface ecg changes (1 trials)
drug-induced qt prolongation (1 trials)
pharmacokinetics (1 trials)
1
Indication
--
Phase 3 Trials
26
Years on Market

Details

Status
Prescription
First Approved
1999-10-01
Routes
ORAL
Dosage Forms
CAPSULE

Companies

Active Ingredient: DOFETILIDE

TIKOSYN Approval History

2000
2001
2002
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2016
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Original
New Indication
New Form
Label Update
30 FDA actions from 1999 to 2019
Aug 2019 SUPPL
Label · Labeling
Mar 2016 SUPPL
Update · REMS
Nov 2015 SUPPL
Update · REMS

What TIKOSYN Treats

2 indications

TIKOSYN is approved for 2 conditions since its original approval in 1999. These indications span multiple therapeutic areas including oncology, immunology, and more.

  • Atrial Fibrillation
  • Atrial Flutter
Source: FDA Label

TIKOSYN Boxed Warning

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 ....

TIKOSYN Competitive Set

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What's emerging in TIKOSYN's indications

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Phase 3 candidates targeting molecules with no FDA-approved drug, in indications TIKOSYN treats. First-in-class if their pivotal trials read out positive.

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Clinical Trial Registry

3 trials
Trial Sponsor ID Phase Status Title
NCT01873950 results posted 13-011D SCR-002 Ph 1 completed Study of the Electrocardiographic Effects of Ranolazine, Dofetilide, Verapamil, and Quinidine in Healthy Subjects
NCT02308748 results posted 14-022D SCR-003 Ph 1 completed Ability of Late Sodium or Calcium Current Block to Balance the ECG Effects of Potassium Current Block
NCT02365532 GS-US-372-1666 Ph 1 completed Effect of Oral GS-6615 on Dofetilide-Induced QT Prolongation, Safety, and Tolerability in Healthy Adults
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Active Pipeline

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Key Completed Trials

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Completed studies with published results, ranked by significance

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Trial Timeline

Full development history with FDA approval milestones

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Understanding FDA Approval Types
Count Type What it means
- ORIG Original approval - drug first enters market
- SUPPL - Efficacy New indication (new disease/condition approved)
- SUPPL - Labeling Label text changes (warnings, dosing updates)
- SUPPL - Manufacturing Production changes (new facility)
- SUPPL - Chemistry Formulation changes (new dosage strength)

Green lines in the timeline show ORIG and Efficacy approvals - the clinically meaningful milestones.

TIKOSYN FDA Label Details

Indications & Usage

FDA Label (PDF)

TIKOSYN is indicated for the treatment of Atrial Fibrillation; Atrial Flutter.

⚠️ BOXED WARNING

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 reg...

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Data Sources

Data sourced from official FDA and NIH databases. Click links to verify on original sources.

How We Calculate These Metrics

Trial Activity Stage

Measures the current development activity pattern based on trial phases, status, and trends. Important: This measures R&D activity, not commercial lifecycle.

Trial statuses: "Active" means recruiting or ongoing. "Completed" means reached planned endpoint. "Terminated" means stopped early—often due to safety, efficacy, or business reasons.

  • Growth: High proportion of early-phase trials (Phase 1/2), active development
  • Expansion: Significant Phase 3 activity, approaching or pursuing approvals
  • Mature: Substantial Phase 4 post-marketing studies
  • Stable: Mixed phase distribution, steady development
  • Declining: Low active trial ratio, reduced R&D investment