Letrasan

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Letrasan

Medically reviewed

Marina Burgos

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Letrasan

Property Description
Active Ingredient Letrozole (INN)
Form Film-coated tablet (Oral route)
Pharmacological Class Aromatase Inhibitor (Third-Generation, Non-Steroidal)
Prescription Status Prescription-Only (Rx)
General Purpose To achieve profound estrogen synthesis inhibition

What is Letrasan and What Type of Medicine is It?

Letrasan is a prescription-only medication whose active ingredient is Letrozole, a highly potent, third-generation Aromatase Inhibitor (AI). It is classified as an antineoplastic agent used in endocrine therapy. Letrozole is a synthetic compound chemically identified as a non-steroidal triazole derivative. The drug's classification as an AI is fundamental, as pharmacological data indicates that this specific class works by blocking the aromatase enzyme, which is critical for estrogen production.

Letrasan is positioned as a Prescription-Only (Rx) medicine due to its powerful systemic action and the nature of the conditions it addresses, setting it apart from non-prescription supplements.


Composition and Form: The Anatomy of Letrozole Tablets

Letrasan is manufactured as a single-ingredient product, containing only the active substance, Letrozole, delivered as a film-coated tablet intended for the oral route. This design provides a convenient method for systemic absorption. Letrozole is characterized as a highly potent substance with high specificity for the aromatase enzyme. This high potency is a key feature, indicating the drug is engineered to achieve a strong and predictable physiological effect.


What is the General Purpose of This Aromatase Inhibitor?

The general purpose of Letrasan is to create a state of significant estrogen synthesis inhibition. Letrozole achieves this by tightly binding to the aromatase enzyme, effectively blocking the final step of the process that converts androgens (precursor hormones) into estrogen within peripheral tissues. This powerful aromatase enzyme blockade significantly lowers the overall level of circulating estrogen, an action utilized in endocrine therapy to modulate or suppress specific hormone-sensitive cellular processes that rely on estrogen for stimulation.

Regulatory References

  1. MedlinePlus
  2. National Cancer Institute (NIH)

What side effects are possible with Letrasan?

Possible Side Effects and Safety Information

The safety profile of Letrasan, containing Letrozole, is structured by adverse reactions classified according to their frequency and the physiological systems affected, based on official regulatory documents. The effects primarily reflect the profound estrogen deprivation achieved by the medication.


Adverse Reaction Classifications

Side effects are officially categorized by frequency, ranging from Very Common to Rare.

  • Very Common reactions (occurring in 10% or more of users) include hot flushes, arthralgia (joint pain), fatigue, and hypercholesterolemia (high blood cholesterol levels).
  • Common reactions (occurring in 1% to less than 10% of users) typically involve headache, nausea, increased sweating, bone pain, peripheral edema, and weight increase.

These reactions are grouped into official System-Organ Classes, such as Musculoskeletal and Connective Tissue Disorders and Vascular Disorders.


Serious Safety Considerations

Official labeling documents certain serious risks. These include the potential for thromboembolic events (e.g., pulmonary embolism, arterial thrombosis) and ischemic cardiac events (e.g., myocardial infarction, stroke). Regulatory documentation also notes rare reports of severe skin reactions.

Long-term exposure is associated with a decrease in Bone Mineral Density (BMD), increasing the risk of osteoporosis and bone fractures; monitoring of both BMD and serum cholesterol is a documented consideration during treatment.

Safety Constraints

The medicine is strictly contraindicated in premenopausal women, women who are pregnant, and women who are lactating. Furthermore, close supervision is advised for patients with severe hepatic impairment due to the potential for increased drug exposure.

Overdose and Emergency Response

Overdose and when to seek help: Official Regulatory Information for Letrasan

Overdose Scope

The information regarding the clinical effects of an acute overdose of Letrasan (Letrozole) is derived from limited documented cases reviewed by regulatory authorities. The highest reported single ingestion of Letrozole was 62.5 mg (equivalent to 25 tablets). In the cases documented, no serious adverse reactions were reported, though data remains limited.

Emergency Actions and Required Help-Seeking

If an overdose is suspected or confirmed, regulatory information mandates that immediate medical attention must be sought. Patients are specifically instructed to contact a doctor or hospital for advice immediately or to call a Poison Control center.

Management and Monitoring

Management Feature Regulatory Statement
Antidote Availability No specific antidote is known; no firm recommendations for definitive treatment can be made.
Management Measures Supportive care and symptomatic treatment are appropriate. Emesis could be induced if the patient is alert.
Monitoring Frequent monitoring of vital signs is considered appropriate for management.

This profile emphasizes immediate regulatory-mandated actions due to the absence of specific reversal protocols, relying instead on observation and general supportive measures.

Therapeutic Uses of Letrasan

What Letrasan Treats: Main Uses and Benefits

Letrasan (Letrozole) is a focused endocrine therapy generally used in postmenopausal women to support the management of hormone receptor-positive breast cancer across different clinical stages. The drug is applied across therapeutic domains where additional symptomatic support is needed. Letrasan is relevant in conditions characterized by periods of heightened symptoms, utilized where therapeutic management assists with maintaining physiological stability.


Therapeutic Applications and Patient Support

This medicine is commonly used after initial treatment, such as surgery, to provide supportive relief against the risk of recurrence (adjuvant and extended adjuvant therapy). It is considered relevant in clinical settings marked by established disease progression (advanced or metastatic breast cancer), where it plays a role in managing progression in this symptomatic domain. In specific scenarios, it is also applied before surgery (neoadjuvant use) in cases requiring temporary assistance in symptom stabilization.

This therapy provides continuous support that helps patients cope more steadily with the risk associated with hormone-sensitive disease. This medication is relevant for managing symptoms that interfere with daily comfort, which assists with maintaining a sense of stability when symptoms are more noticeable.


Quick Fact

Quick Fact: Relief for Disease Progression Letrasan assists with managing symptomatic domains linked to tumor growth by supporting stability, which is relevant when supportive symptom management is appropriate.

Regulatory References

  1. NIH MedlinePlus overview

Eligibility and Restrictions for Use

Who Can and Cannot Use Letrasan?

The population eligibility for Letrasan is strictly defined by regulatory authorities based on endocrine status and specific medical conditions.

Contraindicated Populations

Use is contraindicated and prohibited for the following groups:

  • Premenopausal Women: Those with confirmed premenopausal endocrine status must not use the medicine.
  • Pregnancy and Lactation: Use is prohibited in women who are pregnant or breastfeeding.
  • Hypersensitivity: Patients with known hypersensitivity to Letrozole or its excipients.

Conditional or Restricted Use

Population Regulatory Status
Females of Reproductive Potential Must use effective contraception during and for at least three weeks after treatment.
Severe Hepatic Impairment Requires close supervision; a dose reduction is recommended.
Severe Renal Impairment Insufficient data are available for treatment guidance (CrCl < 10 mL/min).

Age-Group Eligibility

The medicine is indicated for postmenopausal women, including older adults (Geriatric population), for whom no dose adjustment is required. Use is not recommended in the pediatric population (children and adolescents), as safety and efficacy have not been established.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Hormonal Therapies: Letrasan (Letrozole) should not be taken concurrently with tamoxifen, other anti-estrogens, or estrogen-containing therapies (e.g., hormone replacement, certain contraceptives). Co-administration with these agents may diminish the pharmacological action of Letrasan and has been shown to substantially decrease its plasma concentrations, potentially compromising treatment efficacy. This combination is generally avoided as a regulatory precaution.

Metabolism-Based Interactions: Letrasan is known to moderately inhibit the enzyme CYP2C19 in laboratory studies. Caution is indicated when Letrasan is administered at the same time as medicinal products that are primarily eliminated by CYP2C19 and have a narrow therapeutic index, such as phenytoin or clopidogrel. Due to its role as a minor substrate for CYP3A4 and CYP2A6, strong inducers or inhibitors of these enzymes may theoretically alter Letrasan exposure, though this is not commonly cited as a major constraint.

Clinically Insignificant Interactions: Official regulatory studies have indicated that co-administration with products such as cimetidine and warfarin does not result in clinically significant drug interactions. The product's overall interaction profile is primarily defined by the requirement to exclude hormonal co-treatment and exercise caution with specific narrow therapeutic index drugs affected by CYP2C19.

Mechanism of Action

How Letrasan Works

Letrasan (Letrozole) exerts its physiological action solely through the targeted, non-steroidal inhibition of the estrogen synthesis pathway. The mechanism is defined by the molecule's role as a specific competitive inhibitor of the Aromatase enzyme (CYP19A1). This enzyme is responsible for converting androgen precursors into estrogens in peripheral tissues like adipose, muscle, and liver.

Letrozole binds reversibly to the heme iron component within the enzyme's active site, physically blocking the binding of natural substrates and arresting the aromatization reaction. The resulting molecular blockade leads to a rapid, systemic suppression of circulating estrogen levels (Estradiol and Estrone), typically exceeding 90% from baseline.

This reduction is highly selective, as the mechanism does not affect the synthesis of other adrenal steroids, such as Cortisol or Aldosterone. The resulting physiological state of estrogen deprivation limits estrogen-driven cellular signaling. This mechanism is constrained where active ovaries can generate a compensatory Luteinizing Hormone (LH) surge, potentially overriding the peripheral enzyme inhibition.

Dosage and Administration Information

How to Use Letrasan

Letrasan (Letrozole) is a film-coated tablet that must be administered strictly according to established clinical protocols. The medication is intended for use only in women with a clearly established postmenopausal status.


Official Administration Guidelines

Feature Guideline
Route of Administration The tablet must be taken orally.
Standard Dosing Schedule The recommended dose across all approved uses is a single 2.5 mg tablet, administered once daily (qDay).
Timing in Relation to Meals The tablet can be administered with or without food, but should be taken at approximately the same time each day.
Course Duration Treatment duration is typically for 5 years in the adjuvant and extended adjuvant settings, or is continued until tumor progression is evident in patients with advanced disease.
Missed-Dose Rules If a dose is missed, take it as soon as it is remembered. However, if it is almost time for the next scheduled dose (e.g., within 2 or 3 hours), the missed dose should be skipped to return to the regular schedule. Doses should not be doubled to compensate for a missed one.

Special Population Instructions

Population Dosage Adjustment Rule
Older Adults No dose adjustment is required.
Renal Impairment No dose adjustment is required for patients with creatinine clearance ge 10 mL/min.
Severe Hepatic Impairment A dose reduction to 2.5 mg every other day may be required for patients with cirrhosis and severe hepatic dysfunction (Child-Pugh C).

These administration instructions establish a highly standardized protocol for the use of Letrasan, centering on a fixed, once-daily oral dose of 2.5 mg. The protocol requires confirmation of postmenopausal status and dictates specific rules for dose adjustment only in cases of severe liver impairment.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Letrasan

Evidence for Use in Early Adjuvant Treatment

The research exploring Letrasan in the early adjuvant setting—meaning after initial local treatment (e.g., surgery)—is based on large, international Phase III Randomized Controlled Trials (RCTs). These studies were set up to explore the study of Letrasan, observed over a timeframe of up to five years, in postmenopausal women diagnosed with hormone receptor-positive early breast cancer. The researchers were primarily focused on measuring Disease-Free Survival (DFS), an outcome tracking the time interval until a specific event related to the disease, and Overall Survival (OS), an outcome examined in long-term studies. Data show patterns related to the primary outcomes observed in the study populations.

Evidence for Use in Extended Adjuvant Treatment

For women who have successfully completed five years of initial standard hormonal therapy, research has explored the question of continuing treatment with Letrasan over an extended timeframe. This is known as extended adjuvant treatment. The evidence comes from pivotal Phase III RCTs comparing Letrasan to a placebo (an inactive tablet). The outcomes measured included Disease-Free Survival (DFS) and Distant Disease-Free Survival (DDFS), two of the outcomes tracking time to a specific disease event. The research so far indicates data show patterns related to measured outcomes for late recurrence and the incidence of a new primary cancer in the opposite breast.

Evidence for Use in Advanced or Metastatic Disease

Letrasan was studied for use as a first hormonal treatment for postmenopausal women whose hormone receptor-positive breast cancer was locally advanced or metastatic. The research involves Phase III RCTs where Letrasan was evaluated against other hormonal agents in the study. Studies focused on measuring endpoints related to disease progression, such as Time to Progression (TTP) or Progression-Free Survival (PFS), and the Objective Response Rate (ORR), which describes the percentage of patients whose tumors were measured to shrink.

Research Gaps and Uncertainties

While a substantial body of research exists for Letrasan, certain areas of the evidence base are not fully established. For example, long-term effects are not fully established across all measured outcomes, particularly for overall survival, due to the issues with patient crossover in key trials. The optimal duration for extended adjuvant therapy is another area where research is ongoing, and study findings were mixed when different durations were compared. Additionally, data for certain groups remain insufficient to draw strong conclusions, particularly for less common subgroups, meaning results apply only to the populations studied in the large initial trials.

Key Studies & References

  1. Letrozole or Tamoxifen in Treating Postmenopausal Women With Breast Cancer (BIG 1-98) - ClinicalTrials.gov
  2. NICE Guideline NG101: Early and locally advanced breast cancer: diagnosis and management (referencing adjuvant/extended use)

Frequently Asked Questions (FAQ)

Common questions about Letrasan (FAQ)


Q: How quickly does Letrasan start working after taking it?

Letrasan is absorbed rapidly following administration. According to regulatory documents, while the drug starts working quickly to inhibit the aromatase enzyme, the full, stable concentration in the bloodstream (known as steady-state) is generally reached after approximately two to six weeks of consistent daily use.


Q: What is the typical timeframe before knowing if Letrasan is helping?

Official clinical trial results indicate that for advanced disease, the median time until a measurable beneficial response was observed was approximately 9.4 months. The exact timeframe for knowing if the medicine is helping depends on the specific condition being treated and the monitoring approach utilized in a clinical setting.


Q: Is Letrasan considered a chemotherapy drug?

No, Letrasan is classified as an antineoplastic agent used in endocrine therapy and is not a traditional cytotoxic chemotherapy drug. It works by targeting the estrogen synthesis pathway, specifically by blocking the aromatase enzyme.


Q: Is it common to feel tired or fatigued when taking Letrasan?

Yes, regulatory documents list fatigue as a Very Common side effect, meaning it is reported to occur in 10% or more of users. This pattern is consistent with the drug's safety profile, which is based on the body's systemic response to the medicine.


Q: What happens in the body when Letrasan is stopped?

Letrasan is eliminated from the body slowly. According to pharmacokinetic data, the drug has a terminal elimination half-life of about two days. This means it takes several days after the last dose for the medicine to be substantially cleared from the body.


Q: Does Letrasan cause changes in mood or anxiety?

Official safety documents list Depression as a Common side effect, meaning it affects 1% to less than 10% of users. Less frequently, Anxiety and Irritability are listed as Uncommon side effects.


Q: Can Letrasan cause hair thinning or hair loss?

Yes, hair loss, also called alopecia, is included in regulatory safety documents as a Common side effect. This means it is an effect reported by 1% to less than 10% of people using the medicine.


Q: Does Letrasan contain lactose or gluten?

Letrasan tablets often contain lactose as an inactive ingredient (excipient), which is detailed in the full product labeling. Regulatory documents indicate that individuals with known sensitivities, such as rare hereditary problems with lactose, may wish to refer to the full excipient list in the official product information. Information regarding gluten can be checked on the specific product label.


Q: Is Letrasan associated with any specific eye-related side effects?

Yes, official safety documents note that eye-related issues are possible, though they are listed as Uncommon side effects. These include reports of cataract, eye irritation, and blurred vision.


Q: What is the relationship between Letrasan and the risk of developing cataracts?

The official safety profile for Letrasan specifically lists Cataract as an Uncommon side effect.


Q: What are the general rules regarding driving or operating machinery while taking Letrasan?

Regulatory information indicates that Letrasan has a minor influence on the ability to drive or operate machinery. Official labeling states that caution is advised and indicates that individuals may wish to understand how the medication affects them before performing tasks that require concentration.


Q: What is the half-life of Letrasan as described in official documents?

The half-life refers to the time it takes for half of the drug to be eliminated from the body. Official documents describe the terminal elimination half-life of Letrasan as approximately two days.


Q: What is the difference between an 'interaction' and a 'contraindication' for Letrasan?

These terms are used to describe risks in official documents. A contraindication describes a specific situation or condition (such as being pregnant) where the medicine must not be used. An interaction describes when taking the medicine with another substance may change the expected effect of one or both.


Q: Are there any specific foods or drinks I should limit or avoid while taking Letrasan?

Letrasan can be taken with or without food. While there are no specific foods listed for avoidance in regulatory documents, official information notes that consuming alcohol may potentially increase certain side effects, such as dizziness or fatigue.


Q: Does Letrasan interact with herbal supplements like St. John's Wort?

Official regulatory guidance advises caution regarding herbal remedies or supplements that might contain estrogenic properties, particularly those used for menopausal symptoms, as they may reduce the intended effect of Letrasan.


Q: Can Letrasan be taken with blood pressure medication?

Studies on the drug’s metabolism indicate that for many commonly used blood pressure drugs, a clinically significant interaction with Letrasan is unlikely. This is based on how Letrasan is processed in the body by key enzymes.


Q: Can Letrasan be taken if a person has liver problems?

Official instructions state that no dose change is typically needed for mild or moderate liver problems. However, for patients with severe liver impairment, the medicine must be used under close supervision, and official labeling indicates that a dose adjustment may be considered.

How should Letrasan be stored and disposed of?

How to Store and Dispose of Letrasan (Letrozole)

Letrasan tablets must be stored at a Controlled Room Temperature, specifically between 20°C and 25°C (68°F and 77°F), with excursions permitted up to 30°C. To maintain stability, the medicine must be protected from moisture and excessive heat and should be kept in the original, tightly closed container.

Child Safety and Disposal

All medicines, including Letrasan, must be kept out of the sight and reach of children.

Unused or expired tablets should be disposed of via a drug take-back program. If a program is unavailable, the tablets should be mixed with an unappealing substance, sealed in a container, and placed in the household trash. Do not dispose of the tablets by flushing them down a drain.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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