Prescription medication · Class III Antiarrhythmic
dofetilide
Also sold as Tikosyn. This medicine is used to maintain a normal heart rhythm if you have atrial fibrillation or atrial flutter for more than a week, and your heart has been returned to a normal rhythm.
Data updated 2026-05-15
- 10,302
- FDA reportsModerately reported
- 8
- InteractionsFew interactions
- 98% less
- Generic vs brandHuge savings
- $10.66
- Brand price (NADAC)
What the data shows
dofetilide (Tikosyn) is a prescription Class III Antiarrhythmic, reported less often than most tracked drugs (10,302 FDA reports), whose generic costs a fraction of the brand (about 98% less).
Reporting volume reflects how widely a drug is used and studied, not how dangerous it is, a FAERS report documents a temporal association, never proof of cause.
dofetilide (Tikosyn) is a prescription Class III Antiarrhythmic. This medicine is used to maintain a normal heart rhythm if you have atrial fibrillation or atrial flutter for more than a week, and your heart has been returned to a normal rhythm.
Dofetilide (Tikosyn) helps keep your heart in a normal rhythm if you have atrial fibrillation or atrial flutter. It can also help convert these abnormal rhythms back to normal.
Verify with FDA → · CMS NADAC pricing →
Drug Pricing (NADAC)
Brand Price
$10.66/unit
Generic Price
$0.19/unit
Generic Savings
98%
Generic Available
Yes (8 manufacturers)
Pricing data from NADAC (CMS), effective December 18, 2024. Compare all drug costs →
What it does
This medicine is used to maintain a normal heart rhythm if you have atrial fibrillation or atrial flutter for more than a week, and your heart has been returned to a normal rhythm.
Common side effects
Headache, Chest pain, Dizziness
Key warnings
This drug can cause life-threatening heart rhythm problems.
The sections below are summarized in plain English from dofetilide's FDA-approved prescribing information. They describe what the official label says, and are not personal medical advice.
How It Works
Dofetilide belongs to a class of drugs called Class III antiarrhythmics. It works by changing the electrical activity in your heart. This helps to stabilize your heart rhythm and prevent irregular heartbeats.
How to Take It
You will start this medicine in a hospital where your heart can be monitored for at least 3 days. Your doctor will determine the right dose for you based on your kidney function and heart rhythm. Take this medicine twice a day. Make sure you have enough medicine before leaving the hospital.
This is a plain-language summary of dofetilide's FDA labeling, not individualized dosing advice. Ask a pharmacist or prescriber before changing how you take this medication.
Pregnancy & Breastfeeding
Tell your doctor if you are pregnant or plan to become pregnant. It is not known if this medicine will harm your unborn baby. Talk to your doctor about the risks and benefits of taking this medicine while pregnant or breastfeeding.
This is a plain-language summary of dofetilide's FDA labeling, not individualized advice. Ask a pharmacist or prescriber about pregnancy or breastfeeding on this medication.
Missed Dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and continue with your regular schedule.
This is a plain-language summary of dofetilide's FDA labeling, not individualized advice. Ask a pharmacist or prescriber what to do about your specific missed dose.
Storage
Store at room temperature, away from moisture and humidity.
Side Effects (from patient reports)
Based on 10,302 FDA adverse event reports.
Most-reported reactions
Adverse reactions in FAERS for dofetilide, by number of reports
- Irregular heartbeat
Irregular heartbeat
1,059 reports
- Shortness of breath
Shortness of breath
603 reports
- Feeling lightheaded
Feeling lightheaded
552 reports
- Feeling tired
Feeling tired
521 reports
- Death
Death
478 reports
- QT interval on ECG is too long
QT interval on ECG is too long
443 reports
- Headache 387
Headache
387 reports
- Feeling unwell 319
Feeling unwell
319 reports
- Diarrhea 316
Diarrhea
316 reports
- Interaction with another medicine 297
Interaction with another medicine
297 reports
What this shows Bars show how often each reaction was reported, not how likely it is to happen, a report records a temporal association, never proof that the drug caused it.
Reports over time
Adverse-event reports filed for dofetilide each year to the FDA Adverse Event Reporting System (FAERS).
Year-to-year volume tracks usage, prescribing, and scrutiny, not a change in per-patient risk. Source: FDA FAERS.
Where dofetilide sits
dofetilide has more FDA adverse-event reports than 40% of the drugs FAERS tracks. A high position reflects how widely a drug is used and watched, not how dangerous it is.
Percentile across all drugs PlainMeds tracks by FAERS report volume. The dot is dofetilide; the line is the median (50th percentile).
FDA Adverse Event Report Analysis
Detailed analysis of 10,302 reports from the FDA Adverse Event Reporting System (FAERS). Reports span 2004–2025.
Total Reports
10,302
Reports Mentioning Death
799
7.8% of reports — not proof of cause
Hospitalization Reports
2,960
Top Indication
Atrial Fibrillation
Gender Distribution
Age Distribution
Most Reported Adverse Reactions (FAERS)
| # | Reaction | Reports |
|---|---|---|
| 1 | ATRIAL FIBRILLATION | 1,058 |
| 3 | DYSPNOEA | 603 |
| 4 | DIZZINESS | 552 |
| 5 | FATIGUE | 520 |
| 6 | DEATH | 478 |
| 7 | ELECTROCARDIOGRAM QT PROLONGED | 443 |
| 8 | HEADACHE | 387 |
| 9 | MALAISE | 319 |
| 10 | DIARRHOEA | 316 |
| 11 | DRUG INTERACTION | 297 |
| 12 | NAUSEA | 288 |
| 13 | HEART RATE INCREASED | 286 |
| 14 | ASTHENIA | 285 |
| 15 | ARRHYTHMIA | 265 |
| 16 | CARDIAC DISORDER | 248 |
Reactions in Death Reports
Reactions in Hospitalization Reports
Source: FDA FAERS (Adverse Event Reporting System) FDA FAERS (Adverse Event Reporting System) Reports are voluntary and do not establish causation
Serious Warnings
This drug can cause life-threatening heart rhythm problems. To lower this risk, you must start or restart this medicine in a hospital where your heart can be watched closely for at least 3 days. The hospital staff will check your kidney function and heart rhythm regularly.
Known Drug Interactions
Coadministration of BIKTARVY with drugs that are substrates of OCT2 and MATE1 (e.g., dofetilide) may increase their plasma concentrations (see Table 3 ). Clinical Comment Antiarrhythmics: dofetilide ↑ Dofetilide Coadministration is contraindicated due to the potential for serious and/or life-threatening events associated with dofetilide therapy [see Contraindications (4) ] .
Mechanism: The HIV medicine blocks the way your body removes the heart medicine dofetilide, causing it to build up to dangerous levels. High levels of dofetilide can cause life-threatening heart rhythm problems.
What to do: These drugs must not be used together. Your doctor will need to find an alternative treatment to avoid serious heart risks.
Dolutegravir may increase plasma concentrations of drugs eliminated via OCT2 or MATE1 (dofetilide, dalfampridine, and metformin) [see Contraindications ( 4 ), Drug Interactions ( 7.3 )] . Other Agents Antiarrhythmic: Dofetilide ↑Dofetilide Coadministration is contraindicated with TRIUMEQ and TRIUMEQ PD [see Contraindications ( 4 )] .
Mechanism: Dolutegravir blocks the proteins in the kidneys that normally help remove dofetilide from the body. This causes the levels of dofetilide in your blood to rise.
What to do: Do not take these two medications together. Your doctor will need to find an alternative treatment.
7.2 Potential for DOVATO to Affect Other Drugs Dolutegravir, a component of DOVATO, inhibits the renal organic cation transporters (OCT)2 and multidrug and toxin extrusion transporter (MATE)1; thus, it may increase plasma concentrations of drugs eliminated via OCT2 or MATE1 such as dofetilide, dalfampridine, and metformin [see Contraindications ( 4 ), Drug Interactions ( 7.4 ), Clinical Pharmacology ( 12.3 )]. Coadministered Drug Class: Drug Name Effect on Concentration Clinical Comment Antiarrhythmic: Dofetilide ↑Dofetilide Coadministration is contraindicated with DOVATO [see...
Mechanism: One of the medicines in this combination blocks the pathways your kidneys use to get rid of dofetilide. This can lead to dangerously high levels of dofetilide in your system.
What to do: This combination should not be used. Talk to your healthcare provider about using a different medication.
Antiarrhythmics Disopyramide Dofetilide Dronedarone Quinidine a Contraindicated during and 2 weeks after itraconazole treatment.
Mechanism: Itraconazole interferes with the way your body breaks down dofetilide, potentially causing the heart medication to reach dangerous levels.
What to do: Avoid taking these two medicines together and wait two weeks after stopping itraconazole before starting dofetilide.
Clinically Significant Drug Interactions with Clarithromycin Tablets Drugs That Are Affected By Clarithromycin Tablets Drug(s) with Pharmacokinetics Affected by Clarithromycin Tablets Recommendation Comments Antiarrhythmics: Disopyramide Quinidine Dofetilide Amiodarone Sotalol Procainamide Not Recommended Disopyramide, Quinidine: There have been postmarketing reports of torsades de pointes occurring with concurrent use of clarithromycin and quinidine or disopyramide.
Mechanism: Clarithromycin affects how this heart medicine is broken down, which can increase the risk of a life-threatening irregular heartbeat.
What to do: This combination is not recommended and should be avoided to prevent serious heart complications.
This is a plain-language summary of interactions documented in FDA labeling, not individualized advice. Ask a pharmacist or prescriber before combining medications.
Common Questions
What should I do if I feel dizzy after taking this medicine?
Can I drink alcohol while taking this medicine?
Will this medicine cure my atrial fibrillation?
How often will I need to see my doctor while taking this medicine?
Can I take other medicines with dofetilide?
What if I have kidney problems?
What if my heart rate is slow?
How long will I need to take this medicine?
What are the signs of Torsade de Pointes?
Can I stop taking this medicine on my own?
What are the common side effects of dofetilide?
Does dofetilide interact with other medications?
What drug class is dofetilide?
Is there a generic version of dofetilide?
Is dofetilide safe during pregnancy?
Related Medications in Class III Antiarrhythmic
Other drugs grouped near dofetilide - same-class peers and common alternatives.
adenosine
Adenocard
Adenosine (Adenocard) is a medicine used to treat certain types of irregular heartbeats.
Compare with dofetilide →
amiodarone
Cordarone, Pacerone
Amiodarone (Pacerone) is a medicine used to treat life-threatening, irregular heartbeats.
Compare with dofetilide →
atropine
AtroPen
Atropine is a medicine that can temporarily block severe effects on your body.
Compare with dofetilide →
bumetanide
Bumex
Bumetanide is a water pill (diuretic).
Compare with dofetilide →
carvedilol
Coreg
Carvedilol is a medicine that lowers blood pressure and helps your heart work better.
Compare with dofetilide →
Medication Guides
Understanding Drug Interactions
How CYP450 enzymes, inhibitors, and inducers affect your medications
Generic vs Brand Name Drugs
FDA requirements, cost savings, and when the difference matters
Narrow Therapeutic Index Drugs
Why some drugs demand precise dosing and monitoring
Common Drug Interactions
Dangerous medication combinations and how to protect yourself
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What the FDA Data Shows for dofetilide
The FDA label for dofetilide (sold under brand names such as Tikosyn) classifies it as a prescription-only medication in the Class III Antiarrhythmic class. This medicine is used to maintain a normal heart rhythm if you have atrial fibrillation or atrial flutter for more than a week, and your heart has been returned to a normal rhythm. Official labeling lists 3 commonly reported side effects, including Headache, Chest pain, Dizziness.
Post-market surveillance from the FDA Adverse Event Reporting System (FAERS) captures real-world experience. For this drug, FAERS contains 10,302 voluntary reports. The database also lists 8 documented drug interactions derived from FDA labeling, with the top-flagged interaction rated major severity. NADAC pricing from CMS shows a generic unit cost of $0.19 versus $10.66 for the brand - a 98% generic savings.
Report counts do not establish causation, a FAERS entry documents a temporal association, not proof that the drug produced the outcome. Widely prescribed medications naturally accumulate more reports than niche therapies, so raw totals must be interpreted alongside total exposure. Shortage status, recall history, and patent information further shape supply and switching decisions. This page summarizes public FDA data for educational purposes only and is not a substitute for professional medical advice, always consult a licensed healthcare provider before starting, stopping, or changing any medication.
Data Sources
Drug labeling: FDA Drug Labels (SPL/DailyMed). Adverse events: FDA Adverse Event Reporting System (FAERS). Pricing: CMS National Average Drug Acquisition Cost (NADAC).
FAERS reports are voluntary and do not establish causation. Drug interactions are derived from FDA labeling and clinical references. Always consult a healthcare professional before making medication decisions.
Last updated: February 9, 2025
Read our methodology - how this data is sourced, computed, and verified.
Data currency: FDA FAERS adverse-event reports through 2025, CMS NADAC acquisition-cost pricing effective December 2024, compiled and last refreshed May 2026. See our methodology for per-source dates and refresh cadence. Spot a figure that looks wrong? Report a correction.
All federal data sources used on this page
- FDA Orange Book - approved drug products with therapeutic equivalence. accessdata.fda.gov/cder/ob
- FDA DailyMed - NIH-hosted drug labeling for FDA-approved meds. dailymed.nlm.nih.gov
- FDA Adverse Event Reporting System (FAERS) - post-marketing safety surveillance. fda.gov/drugs/faers
- NLM RxNorm - standardized clinical drug nomenclature. nlm.nih.gov/research/umls/rxnorm
- CMS Medicare Part B Drug Average Sales Price Files - federal drug pricing data. cms.gov/medicare/part-b-drugs/asp
- FDA Drug Shortages Database - current and resolved drug shortage tracking. accessdata.fda.gov/drugshortages