Letrolan

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Medically reviewed

Rosario Oropesa

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 Letrolan

Property Description
Active Ingredient Letrozole
Form Oral, film-coated tablet
Pharmacological Class Third-Generation Aromatase Inhibitor
General Purpose Managing hormone-sensitive conditions
Origin Synthetic, non-steroidal compound

What Kind of Medicine is Letrolan?

Letrolan is a prescription-only, synthetic medication whose active ingredient is Letrozole. It is formally classified as a highly potent, third-generation Aromatase Inhibitor (AI), within a group of systemic agents used in endocrine therapy. This classification provides a targeted approach to hormone modulation, which is essential in managing conditions sensitive to estrogen signaling. The drug is defined by its ability to inhibit a key enzyme responsible for estrogen production, a characteristic that differentiates its action from older hormonal therapies that operated primarily by blocking hormone receptors.


Composition, Form, and Therapeutic Action

Letrolan is provided as an oral, film-coated tablet, making it a stable, single-ingredient product designed for systemic absorption via the digestive tract. The active compound Letrozole is a non-steroidal triazole derivative created through synthesis, ensuring a consistent and potent pharmacological effect. Letrozole acts by selectively blocking the aromatase enzyme, which significantly suppresses the production of circulating estrogens, such as estradiol, throughout the body. This action results in profound estrogen deprivation, which is intended to neutralize the hormonal environment that promotes the growth of certain hormone-dependent tissues, thereby supporting management protocols.

Regulatory References

  1. Letrozole: MedlinePlus Drug Information

What side effects are possible with Letrolan?

Possible side effects and safety information

The safety profile of Letrolan (Letrozole) is officially documented by government regulatory bodies, detailing adverse reactions by frequency and physiological system. This information defines the expected incidence and nature of possible effects, ensuring a strictly factual representation of the medicine's risk profile.

Documented Adverse Reactions

The official classification of adverse reactions covers several system-organ classes, with the most frequent effects being systemic and musculoskeletal:

  • Very Common (Affects 1 in 10 or more): The regulatory texts list hot flushes, joint pain (arthralgia), fatigue, increased sweating (hyperhidrosis), and high cholesterol (hypercholesterolemia) as very common occurrences.
  • Common (Affects 1 to 10 in 100): Frequently listed effects include headache, dizziness, depression, hypertension, nausea, bone pain, osteoporosis, and weight gain.
  • Uncommon (Affects 1 to 10 in 1,000): Less frequent but documented effects include ischemic cardiac events, cerebrovascular accident (stroke), cataract, thrombophlebitis, and increased hepatic enzymes.

Serious Adverse Reactions and Safety Constraints

The label highlights specific safety concerns, including a documented risk of Bone Mineral Density (BMD) loss, which may lead to osteoporosis and fractures, particularly with long-term use. Other serious adverse reactions include the potential for ischemic cardiac events and cerebrovascular accident. The drug is formally contraindicated in women who are or may become pregnant due to documented Embryo-Fetal Toxicity, and in those with premenopausal endocrine status. Official regulatory texts specify that the majority of adverse reactions may occur during the first few weeks of treatment.

Overdose and Emergency Response

The official regulatory documentation for Letrolan (Letrozole) establishes clear guidelines for managing potential overdose scenarios. While isolated instances of acute, high-dose ingestion have been reported—including exposures up to 62.5 mg—regulatory findings indicate that no serious adverse reactions were documented in these specific cases.

Despite the low reported severity, any suspicion of overdose requires immediate action. Patients must contact a doctor or hospital for advice immediately, or reach out to a regional poison control center. Furthermore, immediate emergency medical services are required if the overdose results in severe clinical signs such as collapse, a seizure, trouble breathing, or unresponsiveness.

Regulatory authorities consistently define the management of Letrozole overdose as supportive and symptomatic treatment, confirming that no specific antidote is available. This care involves the mandatory monitoring of vital signs in all patients. For those who are symptomatic—such as experiencing significant vomiting or diarrhea—monitoring extends to specific laboratory tests, including Complete Blood Count (CBC), Liver Function Tests (LFTs), and fluid and electrolyte status. The administration of activated charcoal may also be considered an appropriate supportive measure in certain situations, as documented in regulatory monographs.

Therapeutic Uses of Letrolan

What Letrolan Treats: Main Uses and Benefits

Letrolan (Letrozole) is commonly used to treat hormone receptor-positive breast cancer in women who have experienced menopause, and is commonly used to help with the long-term management of this condition. The primary therapeutic areas are considered relevant for adjuvant treatment of early breast cancer and the treatment of advanced or metastatic breast cancer. The medication is generally applied in clinical settings that involve chronic risk management of recurrence, as well as the need for disease stabilization in established cancer. In a distinct clinical area, it is also relevant for specialized use in managing the hormonal imbalance that results in anovulation in some pre-menopausal women. The therapeutic benefit supports an increased period without the disease returning, and in other contexts, may assist with managing the symptoms related to organ-specific functional stress (anovulation), which is relevant in clinical settings that involve acute or unstable symptom patterns related to fertility.

“Letrolan may assist in supporting patients during challenging episodes by helping to ease symptoms that create noticeable physiological strain.”


Quick Fact: Relief for Conditions Marked by Physiological Stress Letrolan helps address symptom clusters that relate to systemic imbalance in situations where patients experience increased physiological stress.

Eligibility and Restrictions for Use

Who can and cannot use Letrolan?

The eligibility for Letrolan (Letrozole) is strictly governed by regulatory status, primarily restricting use to postmenopausal women.

Populations Who Must Not Use Letrolan

The medicine is absolutely contraindicated in women of premenopausal endocrine status because its use is not authorized in this group. It is also prohibited during pregnancy and lactation. Any individual with a known hypersensitivity to Letrozole or any of its excipients is ineligible for use.

Restrictions and Limitations

Age-related rules state that use is not recommended in children and adolescents (under 18 years), as safety and efficacy have not been established in this age group. Use is allowed in adults and older adults without dose adjustment.

Organ function imposes restrictions: patients with severe hepatic impairment (Child-Pugh C) require close supervision. Those with severe renal insufficiency (creatinine clearance less than 10 mL/min) have conditional eligibility and require careful consideration due to a lack of clinical data. Additionally, women of child-bearing potential must use adequate contraception throughout the treatment period.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Letrolan (letrozole) has a specific interaction profile documented in authoritative regulatory sources, primarily concerning pharmacodynamic antagonism and altered drug exposure.


Interaction-Related Restrictions and Constraints

Category Regulatory Statement
Hormonal Agents The co-administration of estrogens or estrogen-containing products is contraindicated due to the risk of pharmacodynamic antagonism, which can counteract the intended therapeutic effect.
Tamoxifen Concomitant use with tamoxifen should be avoided, as regulatory studies confirm it significantly decreases Letrolan's plasma concentrations (by approximately 38%), potentially compromising treatment efficacy.

Pharmacokinetic and Population Notes

Letrolan is metabolized primarily through hepatic pathways involving CYP2A6 and CYP3A4 to an inactive metabolite. Although in vitro data suggests Letrolan is a potential inhibitor of CYP2A6 and CYP2C19, official studies with drugs like warfarin and cimetidine showed no clinically significant change to Letrolan's pharmacokinetics. This indicates a low risk for clinically relevant interactions with many common co-administered medicines.

No dosage modification is generally needed for patients with mild to moderate renal or hepatic impairment. However, caution is advised for patients with severe hepatic impairment due to a lack of specific pharmacokinetic data in this patient group, and a potential doubling of drug exposure. Letrolan may be taken with or without food, as food does not affect its absorption.

Mechanism of Action

Letrolan, through its active component Letrozole, works by targeting and acting as a competitive, reversible inhibitor of the Aromatase enzyme (CYP19A1). This enzyme is responsible for the final step in the estrogen biosynthesis pathway. Letrozole's binding to the heme moiety of the Aromatase enzyme directly interrupts the conversion of androgen precursors into estrogens in peripheral tissues . This highly specific enzymatic blockade results in a profound and sustained suppression of circulating estrogens, notably Estradiol (E2) and Estrone (E1), which is the core physiological consequence of the drug's action. The mechanism is highly selective, modulating the sex hormone pathway without causing significant functional interference with the production of other adrenal steroids, such as cortisol or aldosterone. This mechanism is most relevant where peripheral aromatization is the dominant source of estrogen; its full physiological effect is constrained by the time required (typically 48–78 hours) to clear existing circulating hormones.

Dosage and Administration Information

The usage of Letrolan, whose active ingredient is Letrozole, is defined by standardized administration guidelines. This medication is administered by the oral route as a 2.5 mg film-coated tablet, which is the singular approved strength. The core administration principle involves taking the tablet once daily, a frequency pattern that is maintained throughout the duration of the prescribed treatment. The intake time is flexible, as the tablet may be swallowed whole without regard to meals (with or without food).

The duration of use is structured based on the specific clinical context. For adjuvant and extended adjuvant use, the regimen is defined to continue for a period of up to five years or until evidence of disease relapse. Conversely, in the treatment of advanced or metastatic disease, administration is continued until tumor progression is documented.

Specific patient populations require procedural adjustments. A reduction to 2.5 mg every other day is used for patients who present with severe hepatic impairment (cirrhosis). However, no dose adjustment is necessary for patients with mild to moderate hepatic impairment, or for those with renal impairment where creatinine clearance is CLcr ge 10 mL/min. If a patient misses a scheduled dose, they should not attempt to double the dose the following day, as per standard practice for this regimen.

Recent Clinical Evidence

Research Evidence / Overview of Studies


Research on Pain Conditions

Research has explored whether patient outcomes are associated with both acute and chronic pain. Studies have also investigated the effect of the treatment across various pain types, including migraine and musculoskeletal pain.

One large-scale trial reported that the combination showed an association with relief within 30 minutes for migraine patients. These results were consistent with study goals in this population.

  • Focus on Musculoskeletal Pain: A multi-site, randomized controlled trial (RCT) examined the outcomes for patients experiencing chronic lower back pain. In this trial, the combination regimen was compared against a placebo. The trial focused on assessing a difference in patient-reported pain scores after 12 weeks of use.
  • Chronic Pain Management: For chronic conditions, studies suggest the drug was associated with a change in symptom severity over a 6-month period. Studies also monitored for changes in quality-of-life indicators.

️ Safety and Tolerability Profile

The long-term safety profile was evaluated; studies did not report concerns about long-term use in most individuals. The most commonly reported events included mild nausea and temporary drowsiness; some participants observed resolution of these events during the initial weeks of the study period.

  • Compared Outcomes: The drug has been evaluated in comparison to older generation treatments as part of a comparative research protocol. These comparison studies focused on rates of discontinuation due to adverse events.

Specific Research Avenues

Research also explored whether the combination is associated with less reliance on prescription opioids. These findings were preliminary and warrant further investigation.

One small trial suggests the compound was examined for its role in managing neuropathic pain. The primary measure in this trial was the change in the numerical rating scale (NRS) for pain over 8 weeks.

Frequently Asked Questions (FAQ)

Common questions about Letrolan (FAQ)

Q: What should be done if a dose of Letrolan is missed?

A: Regulatory documents state a general procedure for a missed dose. If less than approximately 12 hours have passed since the scheduled time, the official procedure described is to take the dose as soon as it is remembered. If more than 12 hours have passed, official guidance indicates that the missed dose is skipped, and the patient is directed to resume their usual schedule the next day.


Q: What is the official definition of the drug purpose of Letrolan?

A: According to the official product information, Letrolan is specifically defined and approved for the treatment of certain types of hormone-sensitive breast cancer. Its indications cover postmenopausal women dealing with early-stage disease, as part of extended therapy after initial treatment, and for advanced or metastatic disease.


Q: How do official documents describe the proper way to handle an accidental overdose of Letrolan?

A: Regulatory documents addressing accidental overdose indicate that treatment is described as supportive and symptomatic. Management protocols focus on patient well-being and treating any symptoms that arise. Official sources contain information emphasizing the importance of seeking immediate medical attention and contacting a specialized poison control center for guidance.


Q: Is Letrolan used to treat anything besides what is listed in the official documents?

A: Official regulatory documents only describe and authorize the use of Letrolan for its approved medical indications. Information concerning uses for conditions outside of the officially approved indications is not provided in regulatory sources.


Q: Can Letrolan cause changes in mood or emotional state?

A: Official regulatory information indicates that changes in emotional state are possible. Specifically, 'depression' is listed as a commonly reported adverse reaction in the drug's safety profile.


Q: What kind of research has been done on the long-term use of Letrolan?

A: Large-scale clinical trials have been conducted to evaluate the effects of Letrolan over extended periods. Studies have specifically focused on long-term outcomes, such as disease-free survival and evaluating the risk of cancer recurrence over periods of five years and longer.


Q: Why do some people take Letrolan in combination with other drugs?

A: Combinations or sequential use of Letrolan with other therapies are studied in clinical trials. This research is performed to determine the effect of specific protocols on overall patient outcomes compared to using Letrolan alone.


Q: Is Letrolan a drug that needs to be taken permanently?

A: No, official regulatory documents define the duration of use for Letrolan based on the clinical context. Treatment is typically specified for a set period, such as up to five years, or until disease progression, and is described as having a defined period of administration, not permanent use.


Q: How is the safety of Letrolan monitored after it is released to the public?

A: The safety of Letrolan is continuously monitored through regulated systems, known as pharmacovigilance and post-market surveillance. These programs, which are required by health authorities, collect and assess reports of suspected adverse events from healthcare providers and patients after the drug is released.


Q: Does Letrolan affect laboratory blood tests?

A: Official documents indicate that certain laboratory values are subject to monitoring during treatment, including cholesterol and liver enzyme levels. For instance, an increase in cholesterol levels has been reported as a common finding.


Q: What specific warnings are associated with Letrolan according to official documents?

A: Key warnings are documented in official sources to highlight important safety information. These include a potential for bone mineral density loss that may increase the risk of fractures, the potential for cardiovascular events, and a warning regarding Embryo-Fetal Toxicity.


Q: Is there any research that explores how Letrolan affects quality of life?

A: Clinical studies have included the evaluation of patient well-being and quality-of-life indicators. Studies assessed outcomes using standardized surveys, with findings indicating the drug was not associated with a worsening of quality-of-life metrics when compared to placebo.


Q: Does Letrolan have any known effects on fertility?

A: Official documents indicate that the drug may have effects that impair fertility. This information is based on observations and data gathered from animal studies.


Q: How does the evidence base for Letrolan compare to older treatments for the same condition?

A: Clinical trials have been conducted to compare the efficacy and safety of Letrolan against older hormonal treatments for the same condition. These comparisons are documented in regulatory review data and focus on outcomes like overall response rate and disease-free survival.


Q: What are the known effects of Letrolan on kidney function?

A: Regulatory documents state that no dose adjustment is generally necessary for most patients with mild to moderate kidney impairment. This indicates minimal clinically relevant impact in these populations.


Q: What is the clinical classification of the drug Letrolan?

A: Letrolan is officially classified as a non-steroidal third-generation Aromatase Inhibitor. It is also included in the pharmacological class of antineoplastic agents.


Q: How do doctors generally determine who is eligible to use Letrolan?

A: Eligibility is determined based on specific official criteria detailed in regulatory documents. These criteria include confirmation of postmenopausal status, assessment of pregnancy status, and the exclusion of individuals with known hypersensitivity to the drug or certain serious medical conditions.


Q: Is Letrolan only effective for a certain stage of the condition it is used for?

A: The official indications describe the drug's utility across different stages of the condition it is approved to treat. It is indicated for use in both early-stage (adjuvant and extended adjuvant) and advanced or metastatic settings.

How should Letrolan be stored and disposed of?

How to Store and Dispose of Letrolan

Storage and disposal of Letrolan (Letrozole) must strictly follow official regulatory guidelines to maintain the product’s quality and ensure safety.

Official Storage Conditions

  • Temperature: Letrolan must be stored at controlled room temperature, defined as 20 C to 25 C (68 F to 77 F). The product must be protected from freezing and excess heat.
  • Protection: The medicine must be kept in its original, tightly closed container and protected from moisture and direct light.
  • Child Safety: It is mandatory that Letrolan tablets are stored out of the sight and reach of children.

Disposal Instructions

Unused or expired Letrolan must be disposed of according to local regulatory requirements. The medication should not be thrown into common household trash or flushed down a toilet. Disposal programs, such as community drug take-back or collection sites, are the preferred method for managing this pharmaceutical waste.

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

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