Estropill

Quick links to important sections

Estropill

Method of action: Endocrine Therapy

Treatment option: Anorexia, Cachexia, Cancer, Breast Cancer

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 Estropill

Property Description
Active Ingredient Megestrol Acetate (INN)
Form Oral Tablets or Oral Suspension
Pharmacological Class Progestin, Antineoplastic Agent
Origin Synthetic Derivative (of Progesterone)
Route Oral

What Type of Medicine is Estropill? (Identity and Classification)

Estropill is a prescription-only medication that contains the potent, orally active active ingredient Megestrol Acetate. This compound is a synthetic derivative of the naturally occurring human hormone, Progesterone, classified as a steroidal progestin. The distinctive formulation, available under the Estropill trade name, is specifically designed for oral delivery, offering a standard of care for a specific patient group.

The medicine functions as a Progestin, an agent that acts as an agonist of the progesterone receptor. In clinical use, it is also classified as an Antineoplastic Agent due to its role in specific hormonal therapy regimens. Its established pharmacological profile is clinically recognized for delivering predictable systemic hormonal activity.

Composition and Available Dosage Forms

The formulation is a single-ingredient product, consisting solely of Megestrol Acetate combined with necessary inert pharmaceutical excipients. The compound itself is a white, crystalline solid chemically designated as 17-Hydroxy-6-methylpregna-4,6-diene-3,20-dione acetate.

Estropill is manufactured for Oral administration in two main dosage forms: Oral Tablets and a corresponding Oral Suspension. The availability of both tablets and an aqueous-based suspension ensures the medication is suitable for patients with varying needs regarding ingestion, particularly those who may require ease of administration due to advanced conditions.

General Function and High-Level Purpose

The general function of Estropill is defined by its dual physiological action. It exerts hormonal modulation and, crucially, stimulates centers in the brain to produce a strong Appetite Stimulation effect. Because of this action, the medication is categorized as an Antianorexic and Anticachectic Agent.

Clinical data indicates that megestrol acetate is commonly used to address appetite loss and significant, inexplicable weight loss associated with cachexia syndrome. Therefore, its primary general purpose is to counteract profound, unintentional weight loss and cachexia (wasting syndrome), offering crucial support to improve the patient's nutritional status.

What side effects are possible with Estropill?

The commercial product name Estropill is primarily associated with megestrol acetate in specific formulations (such as oral drops or tablets) authorized in some regions for veterinary use (e.g., controlling estrus in female cats and dogs). Information regarding human-use side effects is derived from the established safety profile of the active ingredient, megestrol acetate, as documented in authoritative regulatory sources for its approved human indications, such as in the palliative treatment of certain cancers or for appetite stimulation.

Serious and Clinically Significant Adverse Reactions

The following serious adverse reactions have been associated with chronic megestrol acetate use and are highlighted in official regulatory labeling for human products:

  • Thromboembolic Events: Increased risk of blood clots, including deep vein thrombosis and pulmonary embolism, especially in patients with a history of these conditions.
  • Adrenal Function: Chronic use may lead to clinical signs of Cushing's Syndrome or cause adrenal insufficiency (low adrenal gland function) upon discontinuation or during stress, which can be life-threatening if not addressed. Symptoms may include hypotension, nausea, vomiting, or weakness.
  • Metabolic Effects: New onset or exacerbation of diabetes mellitus (high blood sugar) has been reported.
  • Fetal Toxicity: The drug is contraindicated in pregnancy due to the risk of fetal harm.

Common Adverse Reactions

The most frequently reported adverse events in clinical trials, occurring in more than 5% of patients in some studies, typically affect the gastrointestinal system or involve general symptoms:

  • Diarrhea
  • Nausea and Vomiting
  • Flatulence (gas)
  • Rash
  • Hypertension (high blood pressure)
  • Impotence (in males)

Other commonly reported reactions include weight gain (often desired in some treatment contexts), decreased sexual desire, and hot flashes. The frequency of other effects—such as amblyopia, carpal tunnel syndrome, or infection—is categorized as common (occurring in 1% to 10% of patients) or uncommon (less than 1%) in official documents.

Population-Specific Safety Considerations

Caution is advised in elderly patients and those with a history of diabetes, thromboembolic disease, or pre-existing adrenal, kidney, or liver conditions. Close monitoring for changes in blood sugar levels is necessary for diabetic patients.

Overdose and Emergency Response

Overdose and when to seek help

Documented Overdose Manifestations Overdose of Estropill (Megestrol Acetate) may be characterized by symptoms reported in post-marketing experience, primarily affecting the gastrointestinal, respiratory, and central nervous systems. Documented manifestations of over-ingestion include diarrhea, nausea, and abdominal pain. Other signs noted in regulatory reports are shortness of breath, cough, listlessness, unsteady gait, and the occurrence of chest pain.

Emergency Response and Supportive Care In all cases of suspected overdose, official regulatory guidelines mandate that the individual seek immediate emergency medical attention or contact the Poison Help line. Management relies on appropriate supportive measures tailored to the clinical presentation, as official prescribing information confirms there is no specific antidote available for megestrol acetate over-ingestion.

Population-Specific Risk The official labeling highlights a specific risk factor related to the body's clearance of the drug. Due to its substantial excretion by the kidney, the risk of toxic reactions may be greater in patients with impaired renal function. This consideration requires particular care for elderly patients, who are at a naturally higher likelihood of having decreased kidney function.

Therapeutic Uses of Estropill

Quick Facts

  • Primary Therapeutic Domain: Weight loss management.
  • Key Use: May offer support for managing weight loss in certain patient populations.

Estropill (Megestrol Acetate) is indicated for the treatment of specific weight-related conditions. This medication is approved for the management of anorexia, cachexia, or significant weight loss when the cause is not fully explained, particularly in patients living with Acquired Immunodeficiency Syndrome (AIDS). The use of this drug may help support weight gain and may contribute to reversing cachexia in this context. It is an established therapeutic option that may be used when clinical assessment determines that intervention for weight stabilization is necessary.

The therapeutic intent of treatment is focused on providing patients with support to address wasting syndrome and related symptoms that may result from their underlying condition. Decisions regarding the use of this medication should be guided by a healthcare professional's evaluation, which considers the full medical profile.

Regulatory References

  1. FDA drug label for megestrol acetate

Eligibility and Restrictions for Use

Eligibility Map: Who Can and Cannot Use Estropill

This section outlines the official population eligibility and non-eligibility status for Estropill (Megestrol Acetate) as defined by authoritative regulatory documents.

Populations for Whom Use is Allowed: Estropill is approved for use in specific adult populations for managing unexplained, significant weight loss associated with HIV/AIDS or for the palliative treatment of advanced breast or endometrial carcinoma.

Populations for Whom Use is Contraindicated: Use is strictly prohibited in patients with a known hypersensitivity to the medicine or any component, and it is contraindicated during pregnancy. Females of reproductive potential must use effective contraception during treatment. Use is not recommended while breastfeeding.

Age-Related Eligibility Rules: The safety and effectiveness have not been established in pediatric patients. Dose selection for older adults must be cautious due to the increased likelihood of reduced renal or hepatic function.

Condition-Specific Eligibility Rules: The medicine requires caution in patients with impaired renal or hepatic function, pre-existing diabetes mellitus, or a history of thromboembolic disease. These conditions necessitate conditional use and careful monitoring.

What should I know about interactions with other medicines?

Interactions with Other Medicines and Products

The regulatory profile for Estropill (Megestrol Acetate) is defined by specific, formally documented interaction patterns with other medications and by constraints related to its elimination pathway. This information is derived strictly from official government prescribing documents.

Drug-Drug Interactions (Official Outcomes)

The co-administration of Estropill with certain medicines leads to officially documented changes in systemic concentration or functional effects:

  • Antiretroviral Agents (Indinavir): Co-administration results in a significant pharmacokinetic interaction, causing a significant decrease in the systemic exposure of Indinavir.
  • Antidiabetic Agents: A pharmacodynamic interaction is documented where co-administration is associated with the exacerbation of pre-existing diabetes mellitus and often requires increased insulin requirements to maintain glucose control.

Restrictions and Clearance Cautions

The official labeling contains two key restrictions and one population caution:

  • The use of Estropill is strictly contraindicated in cases of known or suspected pregnancy.
  • Due to the drug being substantially excreted by the kidney, official cautions note that the risk of elevated plasma concentrations and toxic reactions may be greater in patients with impaired renal function. This same clearance consideration applies to geriatric patients, for whom monitoring of renal function may be necessary.

Regulatory prescribing information does not formally document specific interactions with food, alcohol, or herbal products in the primary drug interaction sections.

Mechanism of Action

Estropill, which contains megestrol acetate, functions as a progestin with agonist activity primarily targeting the intracellular progesterone receptor (PR) in various reproductive and systemic tissues, including the hypothalamus and pituitary gland. As a progesterone receptor agonist, megestrol acetate binds to the PR, causing receptor activation, dimerization, and subsequent translocation of the ligand-receptor complex into the cell nucleus.

Once in the nucleus, the complex interacts with specific progesterone-response elements (PREs) on the genome. This molecular interaction modulates the transcription of target genes, leading to changes in the synthesis of specific proteins. The major downstream effect is an anti-gonadotropic action exerted primarily at the level of the hypothalamus. This involves the suppression of gonadotropin-releasing hormone (GnRH) pulse frequency, which in turn leads to reduced pituitary secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH). This systemic modulation of the hypothalamic-pituitary-ovarian (HPO) axis results in a persistent state of suppressed gonadotropin release and subsequent reduced ovarian steroidogenesis.

Dosage and Administration Information

Estropill is a medication containing Megestrol Acetate that is approved exclusively for oral administration and is available as both an Oral Suspension and Oral Tablets (20 mg and 40 mg). The Oral Suspension is supplied in a standard 40 mg/mL concentration and a concentrated 125 mg/mL strength, with specific administration rules applying to each form.

The standardized adult dosing regimen is based on a once daily (QD) frequency. The recommended starting dose for the standard 40 mg/mL suspension is 800 mg per day. For the concentrated 125 mg/mL suspension, the daily dose is 625 mg; these strengths are not interchangeable on a milligram-per-milligram basis due to differing absorption characteristics. Lower doses, such as 400 mg daily, are also noted as having a clinical effect.

Usage instructions mandate that the medicine must be administered with food to maximize absorption. If the liquid formulation is used, the container must be shaken well immediately prior to measuring the dose with a calibrated device. Treatment duration is typically continued for an adequate period, defined in clinical contexts as a minimum of two months, before the procedural effect is fully assessed.

Guidelines for specific patient populations advise cautious dosing for older adults, often starting at the lower end of the established range. The safety and effectiveness of this medicine for pediatric use have not been established.

Recent Clinical Evidence

Research evidence / Overview of studies for Estropill

Research Evidence Summary: Core Indications Studied

Estropill (megestrol acetate) has been evaluated in multiple clinical studies, primarily Randomized Controlled Trials (RCTs) and comprehensive systematic reviews, focusing on weight loss management. These trials were conducted during periods of increased symptom activity in patients experiencing involuntary, significant weight loss, a condition often marked by functional limitations. The regulatory approvals for Estropill were supported by the results and analysis of these core studies. The research has explored how symptoms are measured in these patient groups and evidence contributes to understanding symptom patterns related to cachexia.


Evidence for Use in AIDS-Related Anorexia and Cachexia

  • The original body of evidence supporting the use of Estropill was evaluated in adult patients with an Acquired Immunodeficiency Syndrome (AIDS) diagnosis who had experienced unintentional and significant weight loss. The primary research base includes short-term, randomized, double-blind, placebo-controlled trials (RCTs).
  • Researchers examined specific measurements, including total body weight, changes in lean body mass, and appetite score improvements, which are outcomes related to physiological strain or stress. Findings describe patterns observed in the studies where measured weight changes were recorded.
  • Follow-up durations were limited, typically 12 weeks. The research provides limited insight into the long-term effects of treatment or the durability of these measured outcomes after the study period ends. As these results apply only to the populations studied, research data for certain groups is limited.

Research Landscape in Cancer-Related Anorexia-Cachexia Syndrome

  • The evidence base for use in cancer-related Anorexia-Cachexia Syndrome (ACS) is derived from a broader collection of RCTs and numerous Systematic Reviews and Meta-analyses evaluated in adult populations with various types of malignancy.
  • Studies explored various outcomes related to physical discomfort, such as total body weight and appetite. Systematic reviews describe patterns related to weight change and appetite scores, but findings were mixed and evidence quality varies across studies.
  • Research on Quality of Life (QOL) was observed in some studies. However, findings often suggest that changes measured during the study period were limited or inconsistent when compared to control groups. The overall evidence quality for some outcomes in this population is often cited as low by systematic reviews due to high inconsistency across trials.

Evidence Gaps and Areas of Uncertainty

The research highlights what is known and what is still uncertain about Estropill. A primary gap documented in scientific reviews is the lack of sufficient research to determine the optimal dose for different patient groups. Furthermore, data for certain groups remain insufficient; for instance, subgroup findings are uncertain for specific populations with multiple pre-existing health conditions.

Key Studies & References

  1. FDA Label and Drug Approval Information for Megestrol Acetate

Frequently Asked Questions (FAQ)

Common questions about Estropill (FAQ)


Q: Is Estropill a type of birth control?

A: Official documents state that Estropill is not intended for use as a preventative measure or for contraception. However, due to the potential hazard to a developing fetus, the medicine is contraindicated in pregnancy. Therefore, women who are able to become pregnant are advised to use effective contraception throughout the course of treatment, and any questions should be discussed with a healthcare provider.


Q: Can Estropill be taken at the same time as my daily vitamin supplement?

A: Regulatory sources focus on formally documented drug-drug interactions. General patient information associated with the drug advises contacting a healthcare provider before taking any new medicine, including over-the-counter medicines or supplements, in order to review the product information for potential interactions.


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

A: Official regulatory prescribing information does not formally document a specific interaction with herbal products, such as St. John's Wort, in the primary drug interaction sections. Information regarding all herbal supplements and medications used is typically reviewed by a healthcare provider.


Q: Are the side effects of Estropill different for older adults?

A: Official documents advise cautious dose selection for older adults due to the greater frequency of decreased liver or kidney function in this population. This cautious approach is noted because impaired function can lead to an increased risk of elevated plasma concentrations and potential for toxic reactions.


Q: Can Estropill change my mood or cause emotional side effects?

A: Yes, official regulatory documents list mood changes as a possible adverse reaction associated with the use of the medicine. Concerns regarding emotional state changes may be reviewed with a healthcare provider.


Q: How long does it typically take to notice the effects of Estropill?

A: Clinical studies indicate that initial benefits, such as an increase in appetite, may begin to appear within 4 weeks of starting treatment. However, official prescribing information notes that treatment is typically continued for a minimum of two months before the procedural effect is fully assessed.


Q: What happens if I accidentally miss taking Estropill one day?

A: Patient information advises that a healthcare provider should be contacted for specific guidance if a dose is missed. It is advised not to take two doses at the same time or to take extra doses to make up for the missed one.


Q: Is it normal to feel tired during the first week of taking Estropill?

A: Official documents list asthenia (a medical term for lack of energy or physical weakness) and malaise as reported adverse reactions associated with the use of the medicine. These effects are possible side effects that may be experienced while taking the medicine.


Q: Are there any specific foods or drinks that should be avoided while using Estropill?

A: Official labeling mandates that the medicine must be administered with food to achieve maximum absorption. Beyond this required condition of use, regulatory prescribing information does not formally document the need to avoid specific foods or drinks.


Q: Is Estropill usually a long-term treatment, or is it for short-term use?

A: The duration of treatment is determined solely by the healthcare provider based on the condition being addressed. Official patient guidance refers to dosage adjustments for those who have taken the medicine for more than a year, indicating that long-term use is a possibility in clinical practice.


Q: Can Estropill cause skin changes, like acne or rashes?

A: Official documents note that a rash is listed as a commonly reported adverse reaction associated with the use of the medicine in clinical trials. The possibility of other skin changes is not reported in the list of most frequent adverse events.


Q: Is there a generic version of Estropill available?

A: Yes, an FDA-approved generic version of the active ingredient, Megestrol Acetate, is available. Generic formulations containing the active ingredient, Megestrol Acetate, are available.


Q: Why do some people say Estropill helps with energy levels?

A: While the adverse event profile includes the possibility of asthenia (lack of energy or weakness), clinical studies have also shown improvements in performance status and overall quality of life in certain patient groups. These improvements may be the source of a perceived benefit to energy levels.


Q: Can Estropill affect my sleep patterns?

A: Yes, official regulatory documents list insomnia (trouble sleeping) as a common side effect associated with the use of the medicine. Concerns about persistent or severe effects may be discussed with a healthcare professional.


Q: Is it possible to be allergic to an ingredient in Estropill?

A: Yes, use of the medicine is contraindicated (strictly prohibited) in patients who have a history of hypersensitivity—which means an allergic reaction—to the active ingredient or any other component used in the formulation.


Q: Does Estropill have any black box warnings from the FDA or similar agencies?

A: The official label includes specific Warnings and Precautions related to serious risks, such as fetal effects, adrenal insufficiency upon withdrawal, and risks for diabetics. However, the product label does not contain a Black Box Warning (the FDA's strongest safety warning).


Q: How long does Estropill stay in your system after you stop taking it?

A: According to pharmacokinetic studies, the plasma elimination half-life of the active ingredient typically ranges from approximately 13 to 105 hours. This means that it takes a number of days for the body to eliminate the medicine after the last dose.


Q: Can Estropill cause changes in vision?

A: Yes, amblyopia (a visual disorder sometimes described as 'lazy eye') is listed in the postmarketing surveillance data as an adverse reaction that has been associated with the medicine.


Q: Is the effectiveness of Estropill affected by stress or sickness?

A: Official warnings relate stress and sickness to safety, noting that in conditions of stress or serious intercurrent illness (such as infection or surgery), extra caution is necessary. Consideration may be given to using supplemental glucocorticoids due to the risk of adrenal insufficiency caused by the medicine.


Q: What is the general expectation for effectiveness based on clinical data?

A: Clinical studies describe that in the specific patient populations studied, a majority experience an increased appetite and weight gain. These changes are associated with documented improvements in appetite scores and a better overall quality of life.


Q: Why is Estropill sometimes associated with migraine headaches?

A: The official label includes a warning that the drug, similar to other progestin medicines, may cause fluid retention (holding excess water). This potential for fluid accumulation could possibly exacerbate (worsen) pre-existing conditions like migraine headaches.


Q: Can I take Estropill if I have high blood pressure?

A: Caution is advised for patients with pre-existing conditions like diabetes or a history of blood clots. Also, hypertension (high blood pressure) itself is listed as a commonly reported adverse reaction associated with the use of the medicine.


Q: What patient groups were included in the main studies for Estropill?

A: The primary clinical studies focused on specific adult populations experiencing unintentional, unexplained weight loss. This included adult patients with an AIDS diagnosis and those with cancer-related Anorexia-Cachexia Syndrome.


Q: Can Estropill affect dental health or cause dry mouth?

A: Yes, dry mouth is listed as an adverse reaction reported in postmarketing surveillance. The presence of dry mouth can, in turn, affect general oral and dental health.

How should Estropill be stored and disposed of?

How to Store and Dispose of Estropill?

Regulatory documents outline specific requirements for the storage, handling, and disposal of Estropill (Megestrol Acetate) to ensure product stability and safety.

Official Storage Conditions

Requirement Rule Based on Regulatory Labeling
Temperature Store at controlled room temperature, typically 20 C to 25 C.
Protection Keep away from heat and moisture.
Prohibition Do not freeze the oral suspension form.
Packaging Store in the tightly closed, original container.

Disposal and Handling

All medications must be stored out of the sight and reach of children for mandatory safety. The official disposal rule is to discard unused or expired product in accordance with local and national regulations.

It is strictly prohibited to dispose of Estropill through household garbage or by flushing it into the sewage system.

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

Available in countries:

Equivalent of Estropill found in:

A-Z Index: