Reported Reactions

Drugs › Angiotensin 2 receptor blocker

Brand name · Losartan potassium

Cozaar: adverse event reports filed with FDA

4,913 reports list it as a suspect or interacting product, 2004–2026. Class: Angiotensin 2 receptor blocker.

4,913
reports as suspect product
0% of all reports · about 218 a year
60
reports, 12 months to June 2026
78 in the 12 months before
70.2%
marked serious by the reporter
67.6% across the class
9.9%
record death among outcomes, as reported
486 reports · not verified by FDA

Between January 2004 and June 2026, 4,913 adverse event reports received by FDA list the brand name Cozaar (losartan potassium) as a suspect or interacting product. Reports that mention it only as a concomitant medication (23,130) are left out of every figure here.

In the 12 months to June 2026, 60 reports listed it, down 23% from 78 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 218 reports a year and 0% of the 20,646,523 reports in the database, and 2% of the reports for the angiotensin 2 receptor blocker class. How many people take it is not in the data, so a count is not a rate of occurrence.

The MedDRA terms listed most often are drug ineffective (7%), dizziness (6.1%) and drug hypersensitivity (5.8%). A report can list several reactions, so shares add to more than 100%; 915 different terms appear across these reports. Drug ineffective is recorded in 7% of these reports, about the same share as in the median angiotensin 2 receptor blocker drug (5.9%).

70.2% of the reports are marked serious by the reporter (67.6% across the class); 9.9% record death among the outcomes and 38.4% record hospitalisation, as reported. 36% of the reports came from consumers, and the largest patient age group is 75 and over (21.3%). 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

068135Jul 2021: 10Aug 2021: 7Sep 2021: 16Oct 2021: 15Nov 2021: 24Dec 2021: 322022Jan 2022: 11Feb 2022: 14Mar 2022: 16Apr 2022: 12May 2022: 6Jun 2022: 11Jul 2022: 10Aug 2022: 8Sep 2022: 12Oct 2022: 15Nov 2022: 9Dec 2022: 142023Jan 2023: 17Feb 2023: 8Mar 2023: 6Apr 2023: 11May 2023: 14Jun 2023: 135Jul 2023: 6Aug 2023: 4Sep 2023: 2Oct 2023: 1Nov 2023: 4Dec 2023: 262024Jan 2024: 2Feb 2024: 1Mar 2024: 3Apr 2024: 11May 2024: 4Jun 2024: 6Jul 2024: 3Aug 2024: 5Sep 2024: 5Oct 2024: 3Nov 2024: 0Dec 2024: 72025Jan 2025: 23Feb 2025: 19Mar 2025: 4Apr 2025: 2May 2025: 3Jun 2025: 4Jul 2025: 1Aug 2025: 2Sep 2025: 3Oct 2025: 2Nov 2025: 0Dec 2025: 42026Jan 2026: 5Feb 2026: 1Mar 2026: 3Apr 2026: 1May 2026: 1Jun 2026: 37

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

01543082004: 26620042005: 2972006: 2372007: 23820072008: 2062009: 2092010: 24420102011: 2092012: 2112013: 26820132014: 2782015: 2622016: 30820162017: 2082018: 2342019: 30220192020: 1982021: 2012022: 13820222023: 2342024: 502025: 6720252026: 48

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Cozaar reports recording the termmedian drug in angiotensin 2 receptor blocker

  1. Drug ineffectivethe medicine did not work as expected7%346
  2. Dizzinesslight-headedness or unsteadiness6.1%299
  3. Drug hypersensitivityan allergic-type reaction to a medicine5.8%287
  4. Blood pressure increaseda raised blood pressure reading4.8%234
  5. Hypotensionlow blood pressure4.6%228
  6. Headachehead pain3.8%185
  7. Dyspnoeashortness of breath3.6%179
  8. Hypertensionhigh blood pressure3.6%178
  9. Coughcough3.3%164
  10. Fatiguetiredness3.3%162
  11. Nauseafeeling sick3.2%156
  12. Diarrhoealoose or frequent stools2.9%142
  13. Malaisegeneral feeling of being unwell2.9%141
  14. Drug interactionan interaction between medicines2.6%126
  15. Astheniaweakness or lack of energy2.5%124
  16. Falla fall2.5%122
  17. Rashskin rash2.5%122
  18. Hyperkalaemiahigh blood potassium2.3%112
  19. Pruritusitching2.1%104
  20. Vomitingbeing sick2%97
  21. Adverse eventan unwanted medical event, type not specified2%96
  22. Painpain, site not specified2%96
  23. Product use in unapproved indicationused for a purpose not on the label2%96
  24. Blood creatinine increasedraised creatinine, a kidney test1.9%92
  25. Palpitationsawareness of the heartbeat1.9%92
  26. Feeling abnormalfeeling odd or not right1.8%90
  27. Pain in extremitypain in an arm or leg1.8%89
  28. Back painback pain1.8%88
  29. Renal failurekidney failure1.8%87

Top 30 of 915 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 24 drugs in the angiotensin 2 receptor blocker 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

Death9.9%486
Life-threatening6%297
Hospitalisation (initial or prolonged)38.4%1,887
Disability4.3%209
Congenital anomaly0.5%23
Other serious35%1,718
Not serious29.8%1,462

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 243,200 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 20.5%24
2 to 110.4%22
12 to 170.4%19
18 to 444.9%243
45 to 6420.5%1,006
65 to 7418.1%887
75 and over21.3%1,047
Age not given33.9%1,665

Patient sex

Female55.2%2,713
Male39.4%1,937
Not given5.4%263

Who reported

Physician32.2%1,580
Pharmacist5%245
Other health professional19.5%957
Lawyer0.5%26
Consumer or non-health professional36%1,767
Not given6.9%338

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 55.2% of reports give the United States as the country of the event or reporter.

Reason for use recorded

Indication as recorded (MedDRA)ReportsShare
Hypertension1,74135.4%
Essential hypertension1222.5%
Blood pressure671.4%
Blood pressure abnormal661.3%
Cardiac failure congestive661.3%
Cardiac failure420.9%

The indication field is filled in by the reporter and is often blank; shares are of all 4,913 reports.

Drugs most often listed in the same reports

Drug (any role in the report)ReportsShare of Cozaar reports
Aspirin4238.6%
Furosemide3026.1%
Amlodipine2475%
Norvasc1994.1%
Hydrochlorothiazide1964%
Metformin1923.9%
Lasix1793.6%
Lipitor1432.9%
Spironolactone1412.9%
Metoprolol1392.8%

Other products listed in reports where Cozaar 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

MeasureCozaarAngiotensin 2 receptor blockerAll reports
Reports as suspect product4,913243,20020,646,523
Share of that pool—2%0%
Reports, latest 12 months60—1,332,454
Marked serious70.2%67.6%57.4%
Death recorded among outcomes, per 1,000 reports9911191
Hospitalisation recorded, per 1,000 reports384287213
Consumer-filed share36%54.2%45.8%
Top term, share of reportsDrug ineffective 7%median 5.9%6.3%

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 angiotensin 2 receptor blocker class

DrugName typeReportsLatest 12 monthsMarked serious
Entrestobrand105,1731,28549.3%
Diovanbrand17,17913391.7%
Valsartangeneric16,93592383.8%
Losartangeneric15,1761,13780.1%
Candesartangeneric10,1971,48798.6%
Irbesartangeneric10,05569293.7%
Benicarbrand8,3707969.4%
Losartan potassiumgeneric6,72524673%
Exforgebrand6,26610895.3%
Diovan HCTbrand5,6703095.3%
Filsparibrand5,5982,90816.1%
Candesartan cilexetilgeneric5,31162297.6%
Olmesartan medoxomilgeneric4,77716990.6%
Telmisartangeneric4,66635791.2%
Atacandbrand4,5974876.6%

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 Cozaar reports

How many adverse event reports has FDA received for Cozaar?

4,913 reports list Cozaar as a suspect or interacting product in the openFDA FAERS release of 28 Sep 2026, covering reports received through June 2026. 60 of them arrived in the latest 12 months. Another 23,130 list it only as a concomitant medication.

What reactions are recorded in Cozaar reports?

drug ineffective (7%), dizziness (6.1%), drug hypersensitivity (5.8%), blood pressure increased (4.8%) and hypotension (4.6%). 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 Cozaar was responsible.

How serious are the reports?

70.2% are marked serious by the reporter. Among the outcomes recorded, 9.9% of reports include death and 38.4% 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 (36%), physician (32.2%) and other health professional (19.5%). Most reports reach FDA through the manufacturer, which must forward reports it receives.

Are reports for Cozaar rising?

60 reports in the 12 months to June 2026, down 23% from 78 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 Cozaar 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 Cozaar?

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 Cozaar as a suspect or interacting product; reports listing it only as a concomitant medication (23,130) 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.