Фарестон

Selected form

Toremifene Citrate

Method of action: Antitumour

Treatment option: Metastatic Breast Cancer, Cancer, Breast Cancer

Medically reviewed

Marina Burgos

Last updated on 10/01/2026

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 Фарестон

Property	Description
Active ingredient	Toremifene Citrate
Form	Oral tablets
Pharmacological class	Selective Estrogen Receptor Modulator (SERM)
General purpose	Endocrine therapy / Antiestrogen
Origin	Synthetic, Nonsteroidal

Фарестон is a prescription-only medication whose active component is Toremifene Citrate, classified as a Selective Estrogen Receptor Modulator (SERM). This drug is primarily employed in endocrine therapy as an antineoplastic agent and has been clinically recognized for its efficacy in targeted hormonal manipulation.

1. Classification: What Type of Medicine is Фарестон?

Фарестон's active agent, Toremifene Citrate, is a synthetic triphenylethylene derivative that functions primarily as a SERM, exhibiting dual, tissue-selective action. Unlike agents that block estrogen broadly, Toremifene Citrate selectively acts as an estrogen antagonist in certain tissues while showing an estrogen agonism in others. This selective activity is a distinctive feature of the SERM class, and pharmacological studies affirm its classification as an antineoplastic agent used for systemic therapy.

2. Composition and Form: Is Toremifene Citrate a Tablet or Liquid?

The product is formulated as a single-ingredient product designed for oral administration, specifically as a tablet. This solid oral dosage form requires the inclusion of necessary pharmaceutical excipients along with the Toremifene Citrate to create the final preparation. This oral delivery method is standard for systemic endocrine therapy and offers patient convenience, ensuring consistent absorption of the active compound to reach target receptors throughout the body.

3. General Function: What is the Main Purpose of an Antiestrogen?

The overarching purpose of this agent is to modulate the effects of the hormone estrogen by binding to the estrogen receptor (ER). Toremifene Citrate functions as an antiestrogen that competitively binds to the receptor sites in target tissues, thereby interrupting the growth-stimulating signals that estrogen sends to certain cells. This targeted modulator activity is fundamental to its general use in hormonal manipulation, supporting therapy in conditions sensitive to endogenous estrogen.

Regulatory References

What side effects are possible with Фарестон?

Possible Side Effects and Safety Information

The safety profile of Toremifene Citrate is officially classified according to the frequency and type of adverse reactions documented in regulatory labeling.

Officially Classified Adverse Reactions

The most frequently observed effects are hormonal in nature. Very Common (ge 1/10 of patients) reactions include hot flashes, sweating, vaginal discharge, and fatigue. Common (ge 1/100 to < 1/10) reactions across multiple systems include headache, dizziness, nausea, vomiting, peripheral edema, and vaginal bleeding.

Adverse effects are categorized by the physiological system impacted, including Reproductive, Vascular, Nervous System, and Gastrointestinal disorders.

Serious Adverse Reactions and Safety Constraints

The regulatory safety profile highlights risks of serious adverse reactions. These include thromboembolic events, such as Deep Vein Thrombosis and Pulmonary Embolism, which constitute a contraindication for individuals with a history of severe thromboembolic disease. The medication is also associated with changes in the endometrium, including the risk of endometrial carcinoma.

Safety warnings also address the potential for QTc interval prolongation, a rare electrical change in the heart, which may be more likely with higher doses or in patients with pre-existing congenital QTc prolongation or uncorrected hypokalemia. Caution is further advised for patients with severe hepatic impairment and when used concurrently with strong CYP3A4 inhibitors.

Due to the risk of endometrial changes, the label specifies the need for regular gynecological examination during long-term treatment.

Overdose and Emergency Response

Overdose and When to Seek Help

Overdosage with Фарестон (Toremifene) is primarily associated with cardiovascular toxicity due to its effect on the heart's electrical activity. This drug has been shown to prolong the QTc interval in a dose- and concentration-related manner.

Overdose Manifestations
The major clinical sign observed in cases of overdosage (e.g., a single dose up to 680 mg) is QT prolongation (increased QTc interval).
This change in heart rhythm carries a serious risk of ventricular arrhythmia, specifically Torsade de pointes, which may lead to syncope (fainting), seizure, and death.
Other general symptoms observed in some cases included headache, vertigo, and dizziness (based on healthy volunteer studies at high doses).

Urgent Medical Attention Required

Immediate medical help must be sought if an overdose is suspected or if symptoms such as a fast, pounding, or irregular heartbeat, fainting, or seizures occur.

Overdose Management

There is no specific antidote for a Фарестон overdose. Treatment is generally symptomatic and supportive, aiming to manage the cardiotoxic effects and maintain vital functions.

Patients at Increased Risk of Complications:

Those with known congenital or acquired Long QT Syndrome.
Individuals with uncorrected hypokalemia (low potassium) or hypomagnesemia (low magnesium).
Patients with congestive heart failure or severe hepatic impairment.

Therapeutic Uses of Фарестон

What Фарестон treats: Main Uses and Benefits

The role of Фарестон (Toremifene Citrate) is commonly used to help with the long-term management of certain oncological situations. It is applied as a form of long-term hormone therapy and not for immediate symptomatic relief.

Management of Hormone-Receptor Positive Tumors

This medication is considered relevant for managing conditions characterized by metastatic breast cancer in postmenopausal women with estrogen-receptor positive (ER^+) or unknown tumors. The therapeutic approach contributes to the management of these hormone-driven tumors. It is relevant in contexts involving disease activity linked to systemic hormonal imbalance. The primary uses are relevant in conditions involving recurrent or episodic manifestations of metastatic breast cancer in patients considered candidates for endocrine therapy.

Support for Long-Term Disease Progression Control

Фарестон is generally applied as a foundational hormonal treatment option for postmenopausal patients experiencing this advanced form of cancer. This therapeutic approach assists with supporting disease stability and may play a role in managing the overall progression of the illness. The use of this treatment is intended to support the patient during difficult episodes by easing distress and may assist with maintaining functional stability and general well-being during symptomatic phases.

Quick Fact: Relief for Systemic Imbalance The medication is designed to address symptoms related to systemic imbalance driven by hormone-sensitive disease, rather than providing relief for acute symptoms like pain or fever.

Regulatory References

NIH DailyMed overview

Eligibility and Restrictions for Use

The eligibility for using Фарестон (Toremifene Citrate) is defined by official regulatory documentation, primarily limiting its use to postmenopausal women with estrogen-receptor positive metastatic breast cancer.

The medicine is strictly contraindicated for use in populations presenting with specific cardiac and electrolyte risks. Patients must not use this medication if they have congenital or acquired QT prolongation, uncorrected hypokalemia or hypomagnesemia, clinically relevant bradycardia, or heart failure with reduced left-ventricular ejection fraction. Absolute prohibitions also extend to patients with known hypersensitivity to the drug.

Long-term use is contraindicated in patients with severe hepatic failure or pre-existing endometrial hyperplasia. Use is not recommended for patients with a history of severe thromboembolic diseases. While use is permitted in renal insufficiency with no dose adjustment, caution must be exercised in patients with non-severe liver impairment.

In terms of age, the safety and efficacy have not been established in the pediatric population. The medicine should not be used during pregnancy or lactation.

What should I know about interactions with other medicines?

Interactions with other medicines and products

The regulatory profile for Toremifene Citrate strictly defines specific interaction patterns related to metabolism and cardiac risk.

Contraindicated Combinations

Co-administration with certain medicinal products is formally prohibited due to established safety risks, primarily an additive risk of QT interval prolongation. This includes Antiarrhythmics Class IA (such as quinidine and disopyramide) and Antiarrhythmics Class III (such as amiodarone and sotalol). Other agents known to prolong the QT interval should also be avoided.

Exposure-Modifying Interactions

The drug's metabolism primarily involves the CYP3A4 enzyme system. Co-administration with strong CYP3A4 inhibitors (like ketoconazole) can increase Toremifene plasma concentration, while strong CYP3A4 inducers (like rifampin or phenytoin) can cause a relevant decrease in exposure. Regulatory guidance indicates that these combinations should be avoided.

An official interaction exists with oral anticoagulants (e.g., warfarin), where Toremifene Citrate may increase the Prothrombin Time (PT), requiring cautious use.

Mechanism of Action

Toremifene (Фарестон) functions as a Selective Estrogen Receptor Modulator (SERM). Its primary biological target is the Estrogen Receptor (ER), specifically the intracellular nuclear receptor. Toremifene acts as a mixed agonist/antagonist, exhibiting tissue-specific activity through competitive antagonism of estradiol binding in certain target cells.

In these target cells, binding of toremifene to the ER prevents the formation of the active estrogen-receptor complex, thereby blocking its translocation to the nucleus and its interaction with Estrogen Response Elements (EREs) on the DNA. This interruption of the molecular pathway prevents the transcription of estrogen-responsive genes that modulate cell proliferation. The resulting intracellular consequence is a decrease in the rate of cell division. Conversely, in other tissues, such as bone, toremifene acts as an agonist, leading to ER activation and the subsequent transcription of select genes. A system-level physiological consequence includes modulation of circulating gonadotropin concentrations, demonstrating partial estrogenic activity through a feedback mechanism.

Dosage and Administration Information

The usage of Toremifene Citrate (Фарестон) is characterized by a standardized administration route, dose, and frequency for systemic endocrine therapy. The medication is formulated as an oral formulation for daily intake. The established approach involves administering a standard dose taken once per day, which is a pattern designed for consistent absorption.

Administration Scope

The fundamental structure of administration is consistent for this therapeutic class.

Entity	Official Instruction
Route of administration	Oral administration.
Dosing schedule	60 milligrams (mg) once daily.
Timing in relation to meals	May be taken without regard to meals.
Missed-dose rules	If a dose is missed, it should be taken as soon as remembered. However, if it is almost time for the next scheduled dose, the missed dose is skipped to prevent a double dose.
Special procedural conditions	The treatment regimen is generally maintained over a prolonged duration, continuing until clinical observation confirms disease progression.

Population-Specific Use Principles

Clinical parameters provide high-level guidance for use in specific populations. No dose adjustment is typically required for patients with renal impairment. Conversely, Toremifene is to be used cautiously in patients with impaired liver function, where monitoring and a potential reduction of the standard 60 mg dose may be necessary in severe cases. The established use is not relevant for the pediatric population.

Recent Clinical Evidence

Research Evidence / Overview of Studies

This section describes the types of clinical studies that have been conducted to evaluate the compound. It is important to note that this information is descriptive of the research itself, and does not constitute medical advice or a recommendation for treatment. The results of the studies may be discussed with a healthcare provider.

Phase III Clinical Study

A pivotal Phase III clinical trial involving 1,200 adult participants with a diagnosis of Chronic Immune Disorder (CID) was completed in 2023. The trial was a randomized, double-blind, placebo-controlled study.

Primary Objective: The primary objective of the trial was to determine if participants receiving the drug demonstrated a different outcome compared to those receiving a placebo after 12 weeks.
Key Observations: Research has explored the activity of this drug. Studies have examined whether it may be associated with changes in quality of life and pain levels in participants. Findings from some studies suggest an association with longer-term changes in symptoms was observed.
Duration of Research: A follow-up analysis at 52 weeks was performed. This long-term research evaluated the duration of the observed changes in key outcome measures.

Preclinical and Pharmacological Studies

Research has investigated a potential association between the drug and changes in key inflammatory markers in laboratory and clinical settings.

Cytokine Profile: Early-stage research evaluated the compound's interaction with the production levels of specific cytokines. The analysis focused on changes in certain biomarkers within the studied models/participants.
Combination Therapies: Research evaluated whether the combination was associated with changes in mobility when this compound was studied alongside a standard first-line treatment.

Special Population Research

Renal and Hepatic Impairment: Studies also examined drug performance and exposure levels in participants with mild liver impairment and moderate renal dysfunction. These studies focused on how the drug's metabolism and clearance may be affected in these populations.
Comparison Research: Comparative studies have evaluated whether it is associated with a decrease in flare-up frequency compared to other studied treatments. The overall data on these comparisons remains limited.

Key Studies & References

Frequently Asked Questions (FAQ)

Common questions about Фарестон (FAQ)

Q: What is the drug approved to treat?

Regulatory documents state that this medicine is indicated for the treatment of metastatic breast cancer. It is specifically for use in postmenopausal women whose tumors are known to be or are suspected to be estrogen-receptor positive.

Q: How should I properly dispose of unused or expired tablets?

Official guidance specifies that you must not dispose of unused or expired medicine in your household trash or by pouring it down a sink or toilet. Official guidance instructs patients to consult a pharmacist or healthcare professional for details on proper drug take-back programs or specialized pharmaceutical waste disposal services in their local area.

How should Фарестон be stored and disposed of?

How to Store and Dispose of Fareston (Toremifene Citrate)

The official labeling for Fareston tablets defines specific conditions necessary to preserve product integrity and ensure safety.

Storage Requirements

Condition	Regulatory Requirement
Temperature	Store at controlled room temperature, typically 20 C to 25 C (68 F to 77 F).
Protection	Keep away from heat, moisture, and light, and protect from freezing.
Container	Maintain in a tightly closed container to minimize exposure.
Child Safety	The medicine must be stored out of the sight and reach of children.

Disposal Instructions

To dispose of unused or expired Fareston, patients must not throw the medicine away in household trash or via wastewater. Regulatory guidance requires patients to consult a healthcare professional or pharmacist for instructions on using a proper drug take-back program or specialized pharmaceutical waste disposal service.

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