Prempro: adverse event reports filed with FDA

19,832

reports as suspect product

0.1% of all reports · about 882 a year

36

reports, 12 months to June 2026

83 in the 12 months before

90.4%

marked serious by the reporter

57.2% across the class

2.6%

record death among outcomes, as reported

523 reports · not verified by FDA

Reports by month, five years

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

2026 covers reports received through June 2026 only.

Reactions recorded in the reports

share of Prempro reports recording the termmedian drug in estrogen

1. Breast cancerbreast cancer39.5%7,824
2. Breast cancer female29%5,744
3. Breast cancer metastatic7.6%1,499
4. Drug ineffectivethe medicine did not work as expected2.1%423
5. Cerebrovascular accidentstroke2%394
6. Oestrogen receptor assay positive1.9%379
7. Deep vein thrombosisa blood clot in a deep vein1.8%350
8. Progesterone receptor assay positive1.7%339
9. Breast cancer in situ1.6%326
10. Hot flusha hot flush1.6%311
11. Pulmonary embolisma blood clot in the lung1.5%300
12. Ovarian cancer1.5%296
13. Myocardial infarctionheart attack1.3%265
14. Thrombosis1.3%249
15. Depressionlow mood1.2%246
16. Anxietyanxiety1.1%209
17. Insomniadifficulty sleeping1%207
18. Malaisegeneral feeling of being unwell0.9%182
19. Feeling abnormalfeeling odd or not right0.9%180
20. Painpain, site not specified0.9%169
21. Headachehead pain0.8%166
22. Vaginal haemorrhagevaginal bleeding0.8%160
23. Fatiguetiredness0.6%123
24. Alopeciahair loss0.6%119
25. Off label useused for a purpose or in a way not on the label0.6%119
26. Weight increasedweight gain0.6%119
27. Nauseafeeling sick0.5%106
28. Hypertensionhigh blood pressure0.5%103
29. Breast operation0.5%99
30. Ovarian cancer metastatic0.5%99

Top 30 of 694 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 25 drugs in the estrogen 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

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 127,523 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

Age and sex as stated in the report; the reporter's qualification is the primary source recorded by FDA. 89% of reports give the United States as the country of the event or reporter.

Reason for use recorded

The indication field is filled in by the reporter and is often blank; shares are of all 19,832 reports.

Drugs most often listed in the same reports

Other products listed in reports where Prempro 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

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 estrogen class

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.

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 Prempro as a suspect or interacting product; reports listing it only as a concomitant medication (3,447) 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.