Reported Reactions

Drugs › Antiarrhythmic

Brand name · Dofetilide

Tikosyn: adverse event reports filed with FDA

6,193 reports list it as a suspect or interacting product, 2004–2026. Class: Antiarrhythmic.

6,193
reports as suspect product
0% of all reports · about 275 a year
30
reports, 12 months to June 2026
92 in the 12 months before
57.5%
marked serious by the reporter
73.5% across the class
6.4%
record death among outcomes, as reported
397 reports · not verified by FDA

6,193 adverse event reports received by FDA list the brand name Tikosyn (dofetilide) as a suspect or interacting product, from January 2004 to June 2026. A further 1,811 reports list it only as a concomitant medication, and those are not counted in the figures on this page.

In the 12 months to June 2026, 30 reports listed it, down 67% from 92 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Over its reporting history that is about 275 reports a year and 0% of the 20,646,523 reports in the database, and 20.1% of the reports for the antiarrhythmic class. How many people take it is not in the data, so a count is not a rate of occurrence.

Reporters most often recorded atrial fibrillation (10.8%), drug ineffective (9.9%) and dizziness (5.5%). A report can list several reactions, so shares add to more than 100%; 651 different terms appear across these reports. Atrial fibrillation is recorded in 10.8% of these reports, a larger share than in the median antiarrhythmic drug (8.2%).

57.5% of the reports are marked serious by the reporter (73.5% across the class); 6.4% record death among the outcomes and 23.4% record hospitalisation, as reported. 55.9% of the reports came from consumers, and the largest patient age group is 75 and over (22.3%). FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event."

Reports by month, five years

01529Jul 2021: 4Aug 2021: 8Sep 2021: 24Oct 2021: 5Nov 2021: 6Dec 2021: 62022Jan 2022: 4Feb 2022: 7Mar 2022: 10Apr 2022: 12May 2022: 29Jun 2022: 11Jul 2022: 9Aug 2022: 23Sep 2022: 13Oct 2022: 11Nov 2022: 22Dec 2022: 162023Jan 2023: 12Feb 2023: 12Mar 2023: 21Apr 2023: 13May 2023: 14Jun 2023: 12Jul 2023: 10Aug 2023: 9Sep 2023: 11Oct 2023: 21Nov 2023: 14Dec 2023: 112024Jan 2024: 24Feb 2024: 17Mar 2024: 15Apr 2024: 14May 2024: 7Jun 2024: 5Jul 2024: 6Aug 2024: 7Sep 2024: 7Oct 2024: 12Nov 2024: 9Dec 2024: 102025Jan 2025: 21Feb 2025: 9Mar 2025: 7Apr 2025: 2May 2025: 2Jun 2025: 0Jul 2025: 1Aug 2025: 1Sep 2025: 6Oct 2025: 6Nov 2025: 1Dec 2025: 42026Jan 2026: 4Feb 2026: 1Mar 2026: 1Apr 2026: 3May 2026: 1Jun 2026: 1

Reports by the month FDA received them. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases.

By year received

03166322004: 21520042005: 1852006: 1402007: 8920072008: 602009: 722010: 62720102011: 2712012: 4082013: 45420132014: 5862015: 6142016: 63220162017: 2932018: 3062019: 49220192020: 1342021: 842022: 16720222023: 1602024: 1332025: 6020252026: 11

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Tikosyn reports recording the termmedian drug in antiarrhythmic

  1. Atrial fibrillationan irregular heart rhythm10.8%668
  2. Drug ineffectivethe medicine did not work as expected9.9%615
  3. Dizzinesslight-headedness or unsteadiness5.5%343
  4. Dyspnoeashortness of breath4.8%298
  5. Electrocardiogram QT prolongeda QT prolongation on the ECG4.3%265
  6. Fatiguetiredness4.2%260
  7. Deaththe patient died; cause not stated by this term3.9%242
  8. Headachehead pain3.7%228
  9. Malaisegeneral feeling of being unwell3.7%228
  10. Drug interactionan interaction between medicines3.5%214
  11. Heart rate increaseda fast heart rate reading3.2%201
  12. Nauseafeeling sick2.6%164
  13. Astheniaweakness or lack of energy2.4%146
  14. Condition aggravatedthe condition being treated got worse2.2%136
  15. Diarrhoealoose or frequent stools2.2%136
  16. Palpitationsawareness of the heartbeat2.1%129
  17. Chest painchest pain2.1%128
  18. Feeling abnormalfeeling odd or not right2%125
  19. Nasopharyngitisa cold1.9%116
  20. Urinary tract infectionbladder or urinary infection1.9%116
  21. Weight decreasedweight loss1.8%112
  22. Coughcough1.8%111
  23. Falla fall1.7%107
  24. Off label useused for a purpose or in a way not on the label1.7%107
  25. Insomniadifficulty sleeping1.7%106
  26. Ventricular tachycardiaa fast rhythm from the lower heart chambers1.6%100
  27. Painpain, site not specified1.6%99

Top 30 of 651 MedDRA preferred terms recorded across these reports, with a plain-language gloss where one is available. One report can record several terms. The hollow bar is the median share across the 11 drugs in the antiarrhythmic class; it describes the reports, not the patients. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Outcomes recorded

Death6.4%397
Life-threatening1.8%111
Hospitalisation (initial or prolonged)23.4%1,451
Disability0.9%58
Congenital anomaly0%1
Other serious40.7%2,518
Not serious42.5%2,633

Outcome flags as the reporter set them; a report can carry several, and "other serious" is FDA's own category for serious reports outside the named outcomes. Grey bar: all 30,807 reports in the class. FDA has not verified any outcome and states that the reports "cannot be used to estimate the incidence of these events."

Patients and reporters

Patient age

Under 20%0
2 to 110%0
12 to 170%2
18 to 440.9%57
45 to 6411%684
65 to 7418.5%1,148
75 and over22.3%1,381
Age not given47.2%2,921

Patient sex

Female44.2%2,738
Male44.7%2,769
Not given11.1%686

Who reported

Physician13%807
Pharmacist12.9%800
Other health professional12.8%790
Lawyer0.1%5
Consumer or non-health professional55.9%3,462
Not given5.3%329

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 95.3% of reports give the United States as the country of the event or reporter.

Reason for use recorded

Indication as recorded (MedDRA)ReportsShare
Atrial fibrillation2,63842.6%
Arrhythmia2263.6%
Cardiac disorder1201.9%
Ill-defined disorder1191.9%
Heart rate irregular821.3%
Atrial flutter651%

The indication field is filled in by the reporter and is often blank; shares are of all 6,193 reports.

Drugs most often listed in the same reports

Drug (any role in the report)ReportsShare of Tikosyn reports
Eliquis4607.4%
Lisinopril4146.7%
Warfarin3976.4%
Metoprolol3966.4%
Coumadin3535.7%
Aspirin3295.3%
Lasix3225.2%
Furosemide2904.7%
Warfarin sodium2524.1%
Xarelto2474%

Other products listed in reports where Tikosyn is a suspect product, whatever their own role. Co-listing means the two were recorded together; it says nothing about either product's part in the event. Only the 2,500 most-reported names are counted here.

In context

MeasureTikosynAntiarrhythmicAll reports
Reports as suspect product6,19330,80720,646,523
Share of that pool—20.1%0%
Reports, latest 12 months30—1,332,454
Marked serious57.5%73.5%57.4%
Death recorded among outcomes, per 1,000 reports6410191
Hospitalisation recorded, per 1,000 reports234339213
Consumer-filed share55.9%36.5%45.8%
Top term, share of reportsAtrial fibrillation 10.8%median 8.2%0.5%

Shares are of reports, not of patients treated. The number of people taking a product is not in the data, so none of these figures is a rate, and differences between columns reflect who takes a product, who reports and how long it has been sold. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic."

Other drugs in the antiarrhythmic class

DrugName typeReportsLatest 12 monthsMarked serious
Multaqbrand5,77328970.9%
Amiodarone hydrochloridegeneric5,28638292.7%
Sotalolbrand3,16812791.9%
Nuedextabrand2,51715526.1%
Dofetilidegeneric1,7283464.4%
Sotalol hydrochloridegeneric1,6415787.9%
Flecainide acetategeneric1,4477887.6%
Propafenonegeneric1,2665692.5%
Propafenone hydrochloridegeneric1,0711880.4%
Dronedaronegeneric7173392.6%

Ordered by report count for navigation only. FDA states that adverse event reports "represent a small percentage of total usage numbers of a product", that "common products may have a higher number of adverse events due to the higher total number of people using the product", and that the data "by themselves are not an indicator of the safety profile of the drug or biologic." A brand and its generic are separate rows because reporters name them separately.

Questions about Tikosyn reports

How many adverse event reports has FDA received for Tikosyn?

6,193 reports list Tikosyn as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 30 of them arrived in the latest 12 months. Another 1,811 list it only as a concomitant medication.

What reactions are recorded in Tikosyn reports?

atrial fibrillation (10.8%), drug ineffective (9.9%), dizziness (5.5%), dyspnoea (4.8%) and electrocardiogram QT prolonged (4.3%). These are MedDRA preferred terms coded from what the reporter described; a report can list several, and a term's presence is not a finding that Tikosyn was responsible.

How serious are the reports?

57.5% are marked serious by the reporter. Among the outcomes recorded, 6.4% of reports include death and 23.4% include hospitalisation. FDA has not verified these outcomes and states that the reports "cannot be used to estimate the incidence" of the events.

Who files these reports?

consumer or non-health professional (55.9%), physician (13%) and pharmacist (12.9%). Most reports reach FDA through the manufacturer, which must forward reports it receives.

Are reports for Tikosyn rising?

30 reports in the 12 months to June 2026, down 67% from 92 in the 12 months before. FDA releases FAERS data quarterly, so the newest months are incomplete and grow in later releases. Counts also move with how many people take a product, its time on the market and publicity.

Do these reports show that Tikosyn was responsible for these reactions?

No. FDA states that "a causal relationship cannot be established between product and reactions listed in a report" and that for any given report "there is no certainty that a suspected drug caused the event." The reaction may relate to the condition being treated, to other medicines, or to something else.

Is this a list of the side effects of Tikosyn?

No. It is a count of what was reported to FDA. The adverse reactions observed in clinical studies are printed on the FDA-approved label, which a pharmacist or clinician can go through with you.

How do I report an adverse event?

Consumers and health professionals can report to FDA through MedWatch (Form FDA 3500 online, or 1-800-FDA-1088), or to the manufacturer, which must pass reports on. See the guide on how to report.

Where this comes from. Counts are built from the openFDA Drug Adverse Event (FAERS) bulk export released 28 Sep 2026, which holds reports FDA received through 30 Jun 2026. Drug names are as reported, resolved to the brand or generic name on the FDA label where openFDA's harmonisation matched them; classes are the pharmacologic class (EPC) from the label and the National Drug Code Directory of 17 Sep 2026. A report counts here when it lists Tikosyn as a suspect or interacting product; reports listing it only as a concomitant medication (1,811) are excluded. No report narrative, lot number, patient detail or reporter identity is published. See the methodology and sources; FDA's record is authoritative, and corrections are handled within five working days.

Drug data (FAERS) through 30 Jun 2026; device data (MAUDE) through 31 Aug 2026. Not medical advice.