Euthyrox (levothyroxine sodium) adverse event reports that FDA received

Name: Reaction terms in FDA adverse event reports that name Euthyrox
Creator: Reported Reactions
License: https://creativecommons.org/publicdomain/zero/1.0/

Name type: Brand name
Generic name: Levothyroxine sodium

What a report is

A report is not proof that the drug was the cause of the event.

FDA says:

Adverse event reports submitted to FDA do not undergo extensive validation or verification. Therefore, a causal relationship cannot be established between product and reactions listed in a report. While a suspected relationship may exist, it is not medically validated and should not be the sole source of information for clinical decision making or other assumptions about the safety or efficacy of a product. Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product.
Source: openFDA, Drug Adverse Event Overview, section "Responsible use of the data". The site read the page on 2 Oct 2026. The data have the reports that FDA received through 30 Jun 2026.

FDA also says:

There is no certainty that the reported event (adverse event or medication error) was actually due to the product. FDA does not require that a causal relationship between a product and event be proven, and reports do not always contain enough detail to properly evaluate an event. The information in these reports has not been scientifically or otherwise verified as to a cause and effect relationship and cannot be used to estimate the incidence of these events.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

Do not rely on openFDA to make decisions regarding medical care. While we make every effort to ensure that data is accurate, you should assume all results are unvalidated.
Source: openFDA, Response of the drug event API (meta.disclaimer). The site read the page on 2 Oct 2026.

Not medical advice. This site counts what was reported to FDA. Questions about a medicine or device belong with a pharmacist or clinician.

Drug reports received through 30 Jun 2026. Device reports have a separate cutoff, 30 Sep 2026. Why a report count is not a rate.

Reports on file

From August 2004 to June 2026, FDA received 3,499 adverse event reports that name Euthyrox. In these reports the drug is a suspect or interacting product.

In the same period, 8,939 further reports name it only as a concomitant medicine. The counts on this page do not include these reports.

FDA received 133 reports in the 12 months to June 2026 and 199 in the 12 months before. FDA releases FAERS data every quarter, so the newest months are not complete. They grow in later releases.

Of the 1,332,454 drug reports that FDA received in the 12 months to June 2026, 133 (under 0.1%) name Euthyrox. Reports for female patients were 80.1% of the reports that name Euthyrox and 52.7% of all drug reports.

The number of people who use the product is not in the data. A count is not a rate. A count of reports is not a count of events or of patients, because one event can have more than one report.

There are many instances of duplicative reports and some reports do not contain all the necessary information.
Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of 11 Mar 2026. The site read the page on 2 Oct 2026.

Suspect product

FDA records each drug in a report as suspect, concomitant or interacting. This page counts the reports in which Euthyrox is suspect or interacting. FDA says:

Any number of the drugs may be marked as suspect if thought to be responsible for one or more of the reactions, but that information is not validated.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

Data version

openFDA FAERS release of 29 Oct 2026. Reports received through 30 Jun 2026.

Since the last update

FDA says:

Many factors can influence whether or not an event will be reported, such as the time a product has been marketed and publicity about an event.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

The information in these reports cannot be used to estimate the incidence (occurrence rates) of the events reported.
Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of 11 Mar 2026. The site read the page on 2 Oct 2026.

The latest update of the FDA data, recorded on 28 Oct 2026, changed no count of this page.

In April to June 2026, FDA received 39 reports that name Euthyrox.
In January to March 2026, FDA received 27.
In April to June 2025, FDA received 43.

April to June 2026 is the latest closed quarter in the data. A closed quarter is a quarter for which the FDA files have most of the reports.

All updates Feed of updates (RSS)

Reaction lookup

These are the reaction terms that the reports record, with the number of reports for each term. Type a term or a plain word to find its count.

What this list leaves out

The table lists the 523 reaction terms that 5 or more reports record. A term with fewer than 5 reports is not in the table.

The site keeps reaction terms for 3,471 of the 3,499 reports (99.2%).

The reports of the other years are not in the counts.

So a count in the table can be lower than the count of FDA.

Find a reaction term

The table shows the first 50 of 523 terms.

Reaction terms in the reports that name Euthyrox, most reports first
Reaction term (MedDRA) and plain meaning	Reports	Share of the 3,499 reports
Fatiguetiredness	697	19.9%
Headachehead pain	475	13.6%
Astheniaweakness or lack of energy	381	10.9%
Dizzinesslight-headedness or unsteadiness	370	10.6%
Insomniadifficulty sleeping	369	10.5%
Alopeciahair loss	344	9.8%
Blood thyroid stimulating hormone increased	314	9%
Anxiety	289	8.3%
Muscle spasmsmuscle cramps	283	8.1%
Nauseafeeling sick	283	8.1%
Palpitationsawareness of the heartbeat	276	7.9%
Myalgiamuscle pain	270	7.7%
Depressionlow mood	262	7.5%
Vertigoa spinning sensation	260	7.4%
Weight increasedweight gain	255	7.3%
Arthralgiajoint pain	242	6.9%
Malaisegeneral feeling of being unwell	228	6.5%
Diarrhoealoose or frequent stools	218	6.2%
Maternal exposure during pregnancythe mother took the medicine during pregnancy	202	5.8%
Loss of personal independence in daily activities	199	5.7%
Dyspnoeashortness of breath	185	5.3%
Disturbance in attentiondifficulty concentrating	183	5.2%
Irritability	181	5.2%
Blood thyroid stimulating hormone decreased	171	4.9%
Weight decreasedweight loss	167	4.8%
Hypertensionhigh blood pressure	166	4.7%
Hyperthyroidismoveractive thyroid	163	4.7%
Hypothyroidismunderactive thyroid	155	4.4%
Tachycardiafast heart rate	151	4.3%
Painpain, site not specified	143	4.1%
Sleep disordera sleep problem	140	4%
Feeling abnormalfeeling odd or not right	139	4%
Somnolencedrowsiness	137	3.9%
Hyperhidrosisexcessive sweating	135	3.9%
Tremorshaking	130	3.7%
Falla fall	125	3.6%
Social avoidant behaviour	124	3.5%
Pain in extremitypain in an arm or leg	114	3.3%
Apathy	111	3.2%
Vomitingbeing sick	111	3.2%
Nervousness	110	3.1%
Arrhythmia	105	3%
Suicide attempta suicide attempt	100	2.9%
Abdominal pain upperupper stomach pain	99	2.8%
Gait disturbancedifficulty walking	97	2.8%
Hot flusha hot flush	97	2.8%
Suicidal ideationthoughts of suicide	95	2.7%
Decreased appetitereduced appetite	94	2.7%
Drug ineffectivethe medicine did not work as expected	92	2.6%
General physical health deteriorationgeneral decline in health	92	2.6%

Download all 523 terms of Euthyrox (CSV)

The counts add to more than 3,499 reports, because one report can record more than one term. FDA says:

No individual drug is connected to any individual reaction. When a report lists multiple drugs and multiple reactions, there is no way to conclude from the data therein that a given drug is responsible for a given reaction.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

The CSV file has the same rows and the same limits. Its last row is a note that says so.

MedDRA term

The person who codes a report selects the preferred term that agrees best with the description of the reporter. The words under a term are the plain meaning that this site gives.

Not the label

The FDA-approved label of a product lists its adverse reactions. See the official pages at the end of this page.

Same ingredient, other names

Reporters write a brand name or a generic name. Each name has its own page and its own count.

Names of Levothyroxine with a page, in the order generic names, brand names, names as reported
Name	Name type	Reports
Levothyroxine	Generic name	15,937
Levothyroxine sodium	Generic name	14,372
Euthyrox (this page)	Brand name	3,499
Levoxyl	Brand name	3,382
Synthroid	Brand name	26,831
Tirosint	Brand name	2,276

Sum of the separately reported names: 66,297. A report that names two of these names is in the sum two times. The sum is not the number of reports for the ingredient.

FDA says:

Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

Importantly, the AEMS data by themselves are not an indicator of the safety profile of the drug or biologic.
Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of 11 Mar 2026. The site read the page on 2 Oct 2026.

Outcomes by year

The table gives the outcomes that the reporters gave, in the terms of FDA.

Outcomes in the reports that name Euthyrox, by the year of the openFDA file that holds the report

The table continues to the right.

Year of the openFDA file	Reports	Serious	Death	Life-threatening	Hospitalization (initial or prolonged)	Disability or Permanent Damage	Congenital Anomaly/Birth Defect	Other Serious (Important Medical Events)	Not serious
2004	3	3	0	0	3	0	0	0	0
2005	4	4	1	0	3	0	0	1	0
2006	4	4	0	0	1	1	0	3	0
2007	2	2	1	0	2	0	0	0	0
2008	6	6	1	2	3	0	0	2	0
2009	3	3	0	0	2	0	0	2	0
2010	5	5	1	2	2	1	0	2	0
2011	1	1	0	0	1	0	0	0	0
2012	21	20	0	0	7	1	0	12	1
2013	75	73	0	2	25	0	1	55	2
2014	96	93	3	0	43	1	0	58	3
2015	51	50	0	3	20	5	1	36	1
2016	22	21	1	0	8	0	2	15	1
2017	40	39	3	6	18	0	1	29	1
2018	698	674	24	7	158	21	6	539	24
2019	697	664	25	10	153	16	6	519	33
2020	517	428	4	14	73	4	4	382	89
2021	243	148	4	5	51	8	0	110	95
2022	286	237	6	7	81	10	5	179	49
2023	244	204	6	8	68	5	9	141	40
2024	230	209	6	3	70	7	2	164	21
2025	167	157	1	9	56	4	2	112	10
2026	84	84	0	3	44	7	0	65	0

An outcome in a report is not proof that the drug was the cause. The reporter gives the outcome, and FDA does not verify it. FDA says:

The information in these reports has not been scientifically or otherwise verified as to a cause and effect relationship and cannot be used to estimate the incidence of these events.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

The six headings with the names of FDA are the outcome terms of FDA. A report can have more than one outcome. The columns Serious and Not serious are the two values of the openFDA field serious. For the value serious, openFDA gives this description:

The adverse event resulted in death, a life threatening condition, hospitalization, disability, congenital anomaly, or other serious condition
Source: openFDA, Drug adverse event fields (YAML reference). The site read the page on 2 Oct 2026.

The year is the year of the openFDA file that holds the latest version of the report. It is not always the year in which FDA first received the report. The chart of the next section uses the year of first receipt. The latest year is not complete.

Reports by year and month

Reports that name Euthyrox, by the year in which FDA received them

The column of 2026 has an outline, because the year is not complete. It has the reports that FDA received through June 2026 only.

Show the figures of the chart as a table

Reports that name Euthyrox, by the year in which FDA received them
Year	Reports
2004	3
2005	4
2006	4
2007	2
2008	6
2009	4
2010	6
2011	1
2012	22
2013	85
2014	95
2015	47
2016	22
2017	125
2018	670
2019	647
2020	539
2021	252
2022	272
2023	235
2024	229
2025	163
2026	66

Reports that name Euthyrox, by month, five years to June 2026

FDA releases FAERS data every quarter, so the newest months are not complete. They grow in later releases.

Why a count moves

A count moves for many reasons. The guide gives FDA's words about them.

Patients and reporters

Age of the patient in the reports that name Euthyrox
Age	Reports	Share
Under 2	42	1.2%
2 to 11	35	1%
12 to 17	48	1.4%
18 to 44	569	16.3%
45 to 64	848	24.2%
65 to 74	422	12.1%
75 and over	363	10.4%
Age not given	1,172	33.5%

Sex of the patient in the reports that name Euthyrox
Sex	Reports	Share
Female	2,802	80.1%
Male	489	14%
Unknown or not given	208	5.9%

Type of reporter in the reports that name Euthyrox
Reporter	Reports	Share
Physician	433	12.4%
Pharmacist	152	4.3%
Other health professional	385	11%
Lawyer	305	8.7%
Consumer or non-health professional	2,025	57.9%
Not given	199	5.7%

Age and sex are as the report gives them. The reporter is the primary source in the report. 10.9% of the reports give the United States as the country.

Reason for use

Reason for use (indication) that the reports of Euthyrox record
Indication as recorded (MedDRA)	Reports	Share
Hypothyroidism	933	26.7%
Post procedural hypothyroidism	272	7.8%
Autoimmune thyroiditis	248	7.1%
Thyroid disorder	198	5.7%
Thyroidectomy	95	2.7%
Basedow's disease	15	0.4%

The reporter fills in the indication, and the field is often empty. Each share is of all 3,499 reports.

Drugs in the same reports

Other drugs that the reports of Euthyrox name, in any role, in order of name
Drug	Reports that name the two
Aspirin	62
Bisoprolol	74
Eliquis	54
Folic acid	57
Ibuprofen	67
Levothyroxine	63
Levothyroxine sodium	50
Omeprazole	60
Pantoprazole	101
Ramipril	61

The table has the 10 drug names that these reports name most. Two names in one report says only that the report recorded the two. It says nothing about the part of a product in the event.

FDA says:

Additionally, it is important to remember that adverse event reports represent a small percentage of total usage numbers of a product. Common products may have a higher number of adverse events due to the higher total number of people using the product.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

Importantly, the AEMS data by themselves are not an indicator of the safety profile of the drug or biologic.
Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of 11 Mar 2026. The site read the page on 2 Oct 2026.

Pages near this one

Levothyroxine same ingredient
Levothyroxine sodium same ingredient
Levoxyl same ingredient
Synthroid same ingredient
Tirosint same ingredient
Eupressyl next in the A to Z list
Eutirox next in the A to Z list
Eupantol next in the A to Z list
Evamist next in the A to Z list
Eumovate next in the A to Z list
Evekeo next in the A to Z list
Eucrisa next in the A to Z list

These links are for navigation. No count selected them.

Official pages

DailyMed labels for EuthyroxThe labels (prescribing information) that have this name, at the National Library of Medicine.
MedWatch Online Voluntary Reporting FormThe online form of FDA for a voluntary report.
MedWatch: The FDA Safety Information and Adverse Event Reporting ProgramThe page of the FDA program that receives reports about drugs and devices.
FDA Adverse Event Monitoring System (AEMS) Public DashboardThe public dashboard of FDA for adverse event reports on drugs and biologics.

The site checked these addresses on 2 Oct 2026. The links open in a new tab.

Cite this page

Reported Reactions. Euthyrox: adverse event reports that FDA received. https://reportedreactions.com/drug/euthyrox/ Source: U.S. Food and Drug Administration, openFDA Drug Adverse Event (FAERS) files, release of 29 Oct 2026. Reports received through 30 Jun 2026.

Where the data come from

The counts come from the openFDA Drug Adverse Event (FAERS) bulk files, release of 29 Oct 2026. The files have the reports that FDA received through 30 Jun 2026. A drug name is the name on the report. The site matches it to a brand name or a generic name of the National Drug Code Directory of 2 Nov 2026. A class is the pharmacologic class (EPC) of the FDA label.

A report is in the count when it names Euthyrox as a suspect or interacting product. The 8,939 reports that name it only as a concomitant medicine are not in the count. The site does not publish a report narrative, a lot number, a detail of a patient or the identity of a reporter. The record of FDA is the authority. See how the site counts reports, the data sources and the corrections page.

Questions

Do these reports show that Euthyrox was responsible for the reactions?

No. FDA says:

For any given report, there is no certainty that a suspected drug caused the event.
Source: FDA, FDA Adverse Event Monitoring System (AEMS) Public Dashboard. Content current as of 11 Mar 2026. The site read the page on 2 Oct 2026.

A reaction can relate to the condition that the drug treats, to other medicines, or to something else.

Is this the list of reactions on the label of Euthyrox?

No. It is a count of what people reported to FDA: 3,499 reports from August 2004 to June 2026. The FDA-approved label of a product lists its adverse reactions. The official pages at the end of this page link to the labels.

Who sent these reports?

Consumer or non-health professional (57.9%), physician (12.4%) and other health professional (11%). These are the types of reporter for the reports that name this drug.

If a manufacturer receives an adverse event report, it is normally required to send the report to FDA.
Source: openFDA, Drug Adverse Event Overview. The site read the page on 2 Oct 2026.

How does a person report an adverse event?

FDA runs MedWatch, a program that takes voluntary reports from health professionals, patients and consumers. The guide on how to report has the links.

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