Letrozole tablet USP for oral administration contains 2.5 mg of letrozole, a nonsteroidal aromatase inhibitor (inhibitor of estrogen synthesis). It is chemically described as 4,4'-(1H-1,2,4-Triazol-1-ylmethylene) dibenzonitrile, and its structural formula is Letrozole is a white to yellowish crystalline powder, practically odorless, freely soluble in dichloromethane, slightly soluble in ethanol, and practically insoluble in water. It has a molecular weight of 285.31, empirical formula C 17 H 11 N 5 , and a melting range of 184°C to 185°C. Letrozole is available as 2.5 mg tablets for oral administration. Inactive Ingredients : Colloidal anhydrous silica, hypromellose, iron oxide yellow , lactose monohydrate, magnesium stearate, microcrystalline cellulose, polyethylene glycol, sodium starch glycolate, starch (corn), talc, and titanium dioxide. Letrozole structural formula

What kind of drug is letrozole?

The FDA classifies letrozole as an aromatase inhibitor. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.

Can you take letrozole with other medicines?

It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run letrozole against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.

What brand names is letrozole sold under?

We track 2 letrozole-containing products in the U.S.: Letrozole and Femara. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.

What forms does letrozole come in?

Across the brands we track, letrozole is currently marketed as tablet, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.

Is there a generic letrozole?

Yes. Our catalog lists 1 generic letrozole product alongside the brand versions. A generic has the same active ingredient and must meet the FDA's bioequivalence standard; it usually costs less. Ask your pharmacist which one your plan covers.

Letrozole: uses, dosing, side effects & brands

Letrozole is an aromatase inhibitor sold in the U.S. under 2 brand and generic names, for breast neoplasms. Below: what the FDA label says, every product that contains it, what the pills look like, and its recall record.

By the pharmaranks editorial teamReviewed against the FDA (openFDA label, NDC Directory & Enforcement) sourcesHow we research

Key facts

Drug class: Aromatase Inhibitor
Treats: Breast Neoplasms
Available as: Tablet
Sold as: 2 products — Letrozole and Femara
Prescription?: Prescription only
Generic available?: Yes
Typical price: about $4 for a 30-count supply

How letrozole is dosed

From the FDA label for Letrozole (application ANDA090838). Other letrozole products — different forms, different strengths — are dosed differently. Follow the label for the one you were prescribed.

Letrozole tablets are taken orally without regard to meals ( 2 ): Recommended dose: 2.5.mg once daily ( 2.1 ) Patients with cirrhosis or severe hepatic impairment: 2.5 mg every other day ( 2.5 , 5.3 ) 2.1 Recommended Dose The recommended dose of letrozole tablet is one 2.5 mg tablet administered once a day, without regard to meals. 2.2 Use in Adjuvant Treatment of Early Breast Cancer In the adjuvant setting, the optimal duration of treatment with letrozole is unknown. In both the adjuvant study and the post approval adjuvant study, median treatment duration was 5 years. Treatment should be discontinued at relapse [see Clinical Studies ( 14.1 )]. 2.3 Use in Extended Adjuvant Treatment of Early Breast Cancer In the extended adjuvant setting, the optimal treatment duration with letrozole tablet is not known. The planned duration of treatment in the study was 5 years. In the final updated analysis, conducted at a median follow-up of 62 months, the median treatment duration for letrozole tablets was 60 months. Seventy-one (71%) percent of patients were treated for at least 3 years and 58% of patients completed at least 4.5 years of extended adjuvant treatment. The treatment should be discontinued at tumor relapse [see Clinical Studies ( 14.2 )]. 2.4 Use in First and Second-Line Treatment of Advanced Breast Cancer In patients with advanced disease, treatment with letrozole tablets…

Letrozole side effects

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 Accord Healthcare Inc. at 1-866-941-7875 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 and tamoxifen. Certain adverse reactions were prospectively specified for analysis (see Table 1), based on the known pharmacologic properties and side effect profiles of the two drugs. Adverse reactions were analyzed irrespective of whether a…

Every letrozole product we track (2)

Same active ingredient — different manufacturer, form, price and FDA recall record. That last one is what our independent score measures.

Letrozole products
#	Drug	Rating	Type	Form	Generic?	Typical price
1	Letrozole	70/100	Prescription	Tablet	Generic	$4	View →
2	Femara	68/100	Prescription	Tablet	Generic

What letrozole pills look like

Imprint codes, colour and shape from the FDA’s labelling data. Match the imprint on your pill — or search any imprint.

Letrozole pill imprints
Imprint	Strength	Colour	Shape	Maker
121;YL	2.5 mg	yellow	round	—
121;YL	2.5 mg	yellow	round	—
LT	2.5 mg	yellow	round	—
LT	2.5 mg	yellow	round	—
FV;CG	2.5 mg	yellow	round	—

Combination products containing letrozole

A combination is a different drug — different dosing, different warnings. It is listed here so you can find it, not so you can substitute it.

Kisqali Femara Co-Pack (Copackaged)

Frequently asked questions

What is letrozole?: Letrozole tablet USP for oral administration contains 2.5 mg of letrozole, a nonsteroidal aromatase inhibitor (inhibitor of estrogen synthesis). It is chemically described as 4,4'-(1H-1,2,4-Triazol-1-ylmethylene) dibenzonitrile, and its structural formula is Letrozole is a white to yellowish crystalline powder, practically odorless, freely soluble in dichloromethane, slightly soluble in ethanol, and practically insoluble in water. It has a molecular weight of 285.31, empirical formula C 17 H 11 N 5 , and a melting range of 184°C to 185°C. Letrozole is available as 2.5 mg tablets for oral administration. Inactive Ingredients : Colloidal anhydrous silica, hypromellose, iron oxide yellow , lactose monohydrate, magnesium stearate, microcrystalline cellulose, polyethylene glycol, sodium starch glycolate, starch (corn), talc, and titanium dioxide. Letrozole structural formula
What kind of drug is letrozole?: The FDA classifies letrozole as an aromatase inhibitor. If you are checking whether it is safe to combine with something else, the class is what matters — two drugs from the same class usually should not be stacked.
Can you take letrozole with other medicines?: It depends on the medicine. We check it against the FDA labels rather than guessing: our interaction checker searches each drug's own label for the other and quotes what it says, naming the section it came from. Run letrozole against whatever else you take — and remember that a label not naming a drug is not the same as that combination being safe.
What brand names is letrozole sold under?: We track 2 letrozole-containing products in the U.S.: Letrozole and Femara. They are the same active ingredient; they differ in form, manufacturer, price and FDA recall record.
What forms does letrozole come in?: Across the brands we track, letrozole is currently marketed as tablet, per the FDA's National Drug Code Directory. Each form is dosed differently — follow the label for the exact product you were prescribed.

Sources: FDA openFDA drug label, National Drug Code Directory, and Enforcement (recall) database. This page reproduces public FDA data and is not medical advice. Dosing is set by your prescriber.