Letairis (ambrisentan) adverse event reports that FDA received

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

Name type: Brand name
Generic name: Ambrisentan
Class: Endothelin receptor antagonist

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 2007 to June 2026, FDA received 49,743 adverse event reports that name Letairis. In these reports the drug is a suspect or interacting product.

In the same period, 13,149 further reports name it only as a concomitant medicine. The counts on this page do not include these reports.

FDA received 58 reports in the 12 months to June 2026 and 74 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, 58 (under 0.1%) name Letairis. Reports for female patients were 75.2% of the reports that name Letairis 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 Letairis 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 13 reports that name Letairis.
In January to March 2026, FDA received 7.
In April to June 2025, FDA received 20.

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 984 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 all 49,743 reports.

The site keeps a term for a year only if two or more reports of that year record it.

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 984 terms.

Reaction terms in the reports that name Letairis, most reports first
Reaction term (MedDRA) and plain meaning	Reports	Share of the 49,743 reports
Dyspnoeashortness of breath	7,802	15.7%
Headachehead pain	3,344	6.7%
Deaththe patient died; cause not stated by this term	3,136	6.3%
Dizzinesslight-headedness or unsteadiness	2,585	5.2%
Fluid retentionthe body holding extra fluid	2,354	4.7%
Fatiguetiredness	2,351	4.7%
Oedema peripheralswelling of the legs, ankles or hands	2,180	4.4%
Pneumonialung infection	2,141	4.3%
Oedemaswelling from fluid	2,048	4.1%
Malaisegeneral feeling of being unwell	1,999	4%
Nasal congestiona blocked nose	1,961	3.9%
Nauseafeeling sick	1,826	3.7%
Cough	1,822	3.7%
Unevaluable eventthe event could not be assessed	1,752	3.5%
Diarrhoealoose or frequent stools	1,672	3.4%
Peripheral swellingswelling of the arms or legs	1,577	3.2%
Chest pain	1,255	2.5%
Swelling	1,200	2.4%
Nasopharyngitisa cold	1,173	2.4%
Hypotensionlow blood pressure	1,068	2.1%
Syncopefainting	1,048	2.1%
Vomitingbeing sick	1,039	2.1%
Astheniaweakness or lack of energy	983	2%
Weight increasedweight gain	904	1.8%
Cardiac failure congestivecongestive heart failure	865	1.7%
Pulmonary arterial hypertension	863	1.7%
Flushingsudden reddening or warmth of the skin	861	1.7%
Anaemialow red blood cells	840	1.7%
Pain in extremitypain in an arm or leg	825	1.7%
Painpain, site not specified	815	1.6%
Falla fall	799	1.6%
Palpitationsawareness of the heartbeat	749	1.5%
Pulmonary hypertensionhigh pressure in the lung arteries	631	1.3%
Drug ineffectivethe medicine did not work as expected	618	1.2%
Chest discomfort	592	1.2%
Oxygen saturation decreased	588	1.2%
Weight decreasedweight loss	555	1.1%
Respiratory failurethe lungs could not supply enough oxygen	546	1.1%
Sinusitissinus infection	540	1.1%
Feeling abnormalfeeling odd or not right	528	1.1%
Pyrexiafever	528	1.1%
Bronchitischest infection	522	1%
Abdominal pain upperupper stomach pain	515	1%
Epistaxisnosebleed	512	1%
Rashskin rash	505	1%
Dyspnoea exertional	491	1%
Constipation	464	0.9%
Decreased appetitereduced appetite	444	0.9%
Influenzaflu	438	0.9%
Pain in jaw	435	0.9%

Download all 984 terms of Letairis (CSV)

The counts add to more than 49,743 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 Ambrisentan with a page, in the order generic names, brand names, names as reported
Name	Name type	Reports
Ambrisentan	Generic name	54,511
Letairis (this page)	Brand name	49,743

Sum of the separately reported names: 104,254. 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 Letairis, 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
2007	68	68	9	0	29	8	0	33	0
2008	536	528	186	23	294	16	0	118	8
2009	811	808	351	25	433	11	0	103	3
2010	1,475	1,464	548	28	862	9	0	116	11
2011	2,548	2,528	757	33	1,680	20	0	204	20
2012	3,222	3,185	844	28	2,178	14	0	372	37
2013	5,060	4,580	1,149	37	3,026	33	1	1,481	480
2014	7,511	5,062	979	14	3,406	33	0	3,491	2,449
2015	23,678	2,685	242	18	1,792	35	0	1,285	20,993
2016	975	473	65	12	329	8	0	208	502
2017	1,050	481	63	7	355	5	0	169	569
2018	984	422	53	10	345	1	0	158	562
2019	541	323	57	8	236	2	1	130	218
2020	428	234	34	7	149	2	0	115	194
2021	335	138	25	4	84	0	0	65	197
2022	186	66	14	0	45	0	0	22	120
2023	126	49	7	1	31	0	0	23	77
2024	107	43	8	3	26	0	0	21	64
2025	82	44	5	1	27	0	0	32	38
2026	20	9	1	0	4	0	0	6	11

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 Letairis, 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 Letairis, by the year in which FDA received them
Year	Reports
2007	59
2008	551
2009	820
2010	1,448
2011	2,549
2012	3,781
2013	8,529
2014	25,207
2015	2,075
2016	996
2017	1,046
2018	962
2019	516
2020	364
2021	329
2022	189
2023	125
2024	99
2025	78
2026	20

Reports that name Letairis, 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 Letairis
Age	Reports	Share
Under 2	14	under 0.1%
2 to 11	258	0.5%
12 to 17	306	0.6%
18 to 44	4,276	8.6%
45 to 64	12,966	26.1%
65 to 74	8,423	16.9%
75 and over	6,807	13.7%
Age not given	16,693	33.6%

Sex of the patient in the reports that name Letairis
Sex	Reports	Share
Female	37,420	75.2%
Male	11,809	23.7%
Unknown or not given	514	1%

Type of reporter in the reports that name Letairis
Reporter	Reports	Share
Physician	7,486	15%
Pharmacist	5,880	11.8%
Other health professional	6,438	12.9%
Lawyer	1	under 0.1%
Consumer or non-health professional	29,246	58.8%
Not given	692	1.4%

Age and sex are as the report gives them. The reporter is the primary source in the report. 99.9% of the reports give the United States as the country.

Reason for use

Reason for use (indication) that the reports of Letairis record
Indication as recorded (MedDRA)	Reports	Share
Pulmonary arterial hypertension	13,626	27.4%
Pulmonary hypertension	8,524	17.1%
Cor pulmonale chronic	990	2%
Scleroderma	445	0.9%
Portopulmonary hypertension	281	0.6%
Connective tissue disorder	203	0.4%

The reporter fills in the indication, and the field is often empty. Each share is of all 49,743 reports.

Drugs in the same reports

Other drugs that the reports of Letairis name, in any role, in order of name
Drug	Reports that name the two
Adcirca	7,139
Aspirin	1,509
Coumadin	2,394
Furosemide	1,621
Lasix	2,360
Oxygen	1,319
Remodulin	3,699
Revatio	6,195
Tyvaso	4,400
Warfarin	1,704

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

Ambrisentan same ingredient
Bosentan same class
Macitentan same class
Opsumit same class
Tracleer same class
Lescol next in the A to Z list
Letermovir next in the A to Z list
Lergigan Promethazine Hydrochloride next in the A to Z list
Letrozol next in the A to Z list
Lergigan next in the A to Z list
Letrozole next in the A to Z list
Lercanidipine hydrochloride next in the A to Z list

These links are for navigation. No count selected them. The class page lists each drug of the class.

Official pages

DailyMed labels for LetairisThe 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. Letairis: adverse event reports that FDA received. https://reportedreactions.com/drug/letairis/ 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 Letairis as a suspect or interacting product. The 13,149 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 Letairis 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 Letairis?

No. It is a count of what people reported to FDA: 49,743 reports from August 2007 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 (58.8%), physician (15%) and other health professional (12.9%). 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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