This grade answers one narrow question: how strong is the public evidence and safety record behind this drug, and how clean is its money trail and court record? It is not a verdict on whether the drug is right for you.
Listed on the WHO Model List of Essential Medicines: a global expert panel judged it among the medicines a health system should always have, on evidence of value, not marketing.
Letrozole tablets are an aromatase inhibitor indicated for: Adjuvant treatment of postmenopausal women with hormone receptor positive early breast cancer ( 1.1 ) Extended adjuvant treatment of postmenopausal women with early breast cancer who have received prior standard adjuvant tamoxifen therapy ( 1.2 ) First and second-line treatment of postmenopausal women with hormone receptor positive or unknown advanced breast cancer ( 1.3 ) 1.1 Adjuvant Treatment of Early Breast Cancer Letrozole tablets are indicated for the adjuvant treatment of postmenopausal women with hormone receptor positive early breast cancer. 1.2 Extended Adjuvant Treatment of Early Breast Cancer Letrozole tablets are indicated for the extended adjuvant treatment of early breast cancer in postmenopausal women, who have received 5 years of adjuvant tamoxifen therapy. The effectiveness of letrozole tablets in extended adjuvant treatment of early breast cancer is based on an analysis of disease-free survival in patients treated with letrozole tablets for a median of 60 months [see Clinical Studies (14.2 , 14.3) ] . 1.3 First and Second-Line Treatment of Advanced Breast Cancer Letrozole tablets are indicated for first-...
Pregnancy: Letrozole can cause fetal harm [see Use in Specific Populations (8.1) ] . Pregnancy: Letrozole can cause fetal harm [see Use in Specific Populations (8.1) ] . Known hypersensitivity to the active substance, or to any of the excipients [see Adverse Reactions (6) ] . Known hypersensitivity to the active substance, or to any of the excipients [see Adverse Reactions (6) ] . Pregnancy ( 4 ) Known hypersensitivity to the active substance, or to any of the excipients ( 4 )
Decreases in bone mineral density may occur. Consider bone mineral density monitoring ( 5.1 ) Increases in total cholesterol may occur. Consider cholesterol monitoring. ( 5.2 ) Fatigue, dizziness and somnolence may occur. Exercise caution when operating machinery ( 5.4 ) Embryo-Fetal toxicity: Can cause fetal harm when administered to pregnant women. Obtain a pregnancy test in females of reproductive potential. Advise females of reproductive potential to use effective contraception ( 5.6 , 8.1 , 8.3 ) 5.1 Bone Effects Use of letrozole tablets may cause decreases in bone mineral density (BMD). Consideration should be given to monitoring BMD. Results of a safety study to evaluate safety in the adjuvant setting comparing the effect on lumbar spine (L2-L4) BMD of adjuvant treatment with letrozole to that with tamoxifen showed at 24 months a median decrease in lumbar spine BMD of 4.1% in the letrozole arm compared to a median increase of 0.3% in the tamoxifen arm (difference = 4.4%) ( P <0.0001) [see Adverse Reactions (6) ] . Updated results from the BMD substudy (MA-17B) in the extended adjuvant setting demonstrated that at 2 years patients receiving letrozole had a median decrease fro...
The following adverse reactions are discussed in greater detail in other sections of the labeling. Bone effects [see Warnings and Precautions (5.1) ] Increases in cholesterol [see Warnings and Precautions (5.2) ] Fatigue and Dizziness [see Warnings and Precautions (5.4) ] The most common adverse reactions (greater than 20%) were hot flashes, arthralgia; flushing, asthenia, edema, arthralgia, headache, dizziness, hypercholesterolemia, sweating increased, bone pain; and musculoskeletal ( 6 ). To report SUSPECTED ADVERSE REACTIONS, contact AvKARE, Inc. at 1-855-361-3993 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reactions rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Adjuvant Treatment of Early Breast Cancer In study, BIG 1-98, the median treatment duration of adjuvant treatment was 60 months and the median duration of follow-up for safety was 96 months for patients receiving letrozole tablets and tamoxifen. Certain adverse reactions were pr...
Contraindications ( 4 ) 7/2017 Warnings and Precautions, Embryo-Fetal Toxicity ( 5.6 ) 7/2017
Source: FDA SPL label for LETROZOLE (AvPAK), effective 20260120. Full label on DailyMed.
These are counts of reports people filed, not rates of harm. Anyone can file one, and nobody checks whether the drug was the cause. Millions of doses are taken for every report sent, so the useful part is how this drug compares with the average across all drugs.
| 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | 2025 | 2026 |
|---|---|---|---|---|---|---|---|
| 6,155 | 6,240 | 6,322 | 5,840 | 5,922 | 5,020 | 4,534 | 2,069 |
13,439 reports blaming this drug for every million Medicare prescriptions filled, which is 4.9× the typical drug on this site. (11,579 reports in 2024–2026, against 861,594 Medicare fills in one year. This is the one number here that accounts for how many people take the drug.)
Source: the FDA's Adverse Event Reporting System (FAERS). Reports are voluntary and unverified. Drugs that are prescribed a lot, in the news, or in lawsuits attract more reports, so the percentages are compared with the whole database to correct for that partly, not fully.
Counts measure how much evidence exists and how transparent it is, not how big the benefit is. For that, ask your prescriber: if 100 people like me took this, how many would get better because of it, and how many would be harmed? (Doctors call these the "number needed to treat" and "number needed to harm.") It differs by condition and is the number drug ads leave out. Sources: PubMed, ClinicalTrials.gov.
In 2024, drug companies reported $0 in payments to US physicians and hospitals tied to this drug across 0 transactions.
No pending federal MDL names this drug or its brands.
Not named in any federal pharmaceutical settlement of $100M or more on record.
Sources: CMS Open Payments (Sunshine Act); Judicial Panel on Multidistrict Litigation pending docket list; DOJ settlements as tabulated on Wikipedia with links to the primary record. State-court and individual suits are not included.
| Product | Fills | $/fill |
|---|---|---|
| Letrozole | 860,689 | $22 |
| Femara | 905 | $1,448 |
1 drug in the same class grades a letter or more higher than letrozole on this site. Worth asking whether one of them would do the same job for you.
Same ATC pharmacological class, graded ones first, best grade at the top. Being in the same class does not make them interchangeable for your condition; it makes them worth asking about.