Felipil

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Felipil

Method of action: Endocrine Therapy

Treatment option: Anorexia, Cachexia, Cancer, Breast Cancer

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 Felipil

Property Description
Active ingredient Megestrol acetate
Form Tablets, Oral Suspension
Pharmacological class Progestin, Antineoplastic agent
General purpose Hormonal modulation and appetite stimulation
Origin Synthetic derivative of progesterone

What Kind of Medicine is Felipil and What is it Made Of?

Felipil is a prescription-only pharmaceutical preparation containing the active ingredient megestrol acetate. It is technically defined as a progestin, placing it in the synthetic hormone class, and is clinically recognized as an antineoplastic agent (anti-cancer medicine). The substance itself is a man-made chemical derivative of the natural human hormone, progesterone, which is engineered to be highly potent and stable when taken orally. Felipil is supplied for oral administration in two distinct dosage forms: solid tablets and a liquid oral suspension. The existence of the suspension provides a key differentiating factor, potentially making precise administration easier for patients who struggle with swallowing solid forms.

General Purpose and Action of this Progestin

The general purpose of this medicine is to leverage its powerful hormonal and metabolic activity to manage specific, complex physiological conditions. Megestrol acetate works primarily by acting as a strong agonist of the progesterone receptor, where it mimics and amplifies the effects of progesterone. This medicine is principally used for managing hormone-sensitive malignancies and treating cachexia, or severe, involuntary weight loss. This clinical recognition establishes the medicine's role in both modulating cellular growth signals and improving nutritional status. Felipil is also distinguished by its significant orexigenic effect, functioning as a powerful appetite stimulant. The dual actions of hormone modulation and appetite stimulation allow the medicine to provide therapeutic support for specific cellular imbalances and profound nutritional decline.

Regulatory References

  1. Megestrol: MedlinePlus Drug Information

What side effects are possible with Felipil?

Possible Side Effects and Safety Information

The safety profile of Felipil (megestrol acetate) is defined by officially documented adverse reactions that are categorized by both frequency and the physiological system affected, consistent with regulatory frameworks like the FDA and EMA.

Frequency and System Classification

Adverse reactions are grouped into system-organ classes (SOC) where the most frequently reported effects involve Metabolism and Nutrition Disorders and Gastrointestinal Disorders.

  • Very Common Reactions: The most frequently documented reactions include weight gain and thrombophlebitis (inflammation of a vein associated with a clot).
  • Common Reactions: Other officially listed common effects include nausea, diarrhea, flatulence, hot flashes, hypertension, and reproductive effects such as impotence in males or breakthrough uterine bleeding in females.

Serious Adverse Reactions and Safety Constraints

The official labeling notes that the medicine carries a risk of serious adverse reactions, particularly those affecting the vascular and endocrine systems. Thromboembolic events, such as pulmonary embolism and deep vein thrombosis, are documented risks.

Furthermore, adrenal suppression or adrenal insufficiency has been reported, especially following the withdrawal of the medicine after long-term use. The medication is also associated with glucocorticoid effects, which may lead to or exacerbate diabetes mellitus or impaired glucose tolerance.

Safety notes also address specific populations. The medicine is strictly contraindicated during pregnancy due to the officially documented potential for fetal harm. Caution is advised for the geriatric population and in patients with a history of thromboembolic disease.

Overdose and Emergency Response

Overdose and When to Seek Help

The official regulatory documentation from government authorities provides specific descriptions concerning overdose of Felipil (megestrol acetate). Based on controlled studies, the prescribing information notes that chronic administration of dosages as high as 1600 mg/day did not result in documented serious unexpected toxicological effects, suggesting a high safety margin at these levels.

Documented Manifestations

Despite the findings of low acute toxicity, specific symptoms have been reported in the post-marketing setting following overdose. These documented manifestations include:

  • Gastrointestinal: Diarrhoea, nausea, and abdominal pain.
  • Systemic: Shortness of breath, cough, unsteady gait, listlessness, and chest pain.

Regulatory-Mandated Emergency Actions

In the event of a suspected overdose, immediate medical attention is required. The official regulatory instruction is that appropriate supportive measures must be taken promptly. Management is defined as symptomatic and supportive treatment, given that there is no specific antidote known for megestrol acetate. Furthermore, official documentation notes a procedural constraint: dialysis is postulated to be an ineffective procedural intervention due to the drug’s inherent low solubility, a factor that affects monitoring requirements.

Therapeutic Uses of Felipil

The therapeutic use of Felipil (megestrol acetate) is generally applicable across two distinct clinical domains.

Treating Severe Loss of Appetite and Wasting Syndromes (Cachexia)

This medicine is commonly used to help address the debilitating symptom cluster of anorexia (severe loss of appetite) and cachexia (involuntary, significant body mass loss). It is commonly used to help manage these symptoms in patients experiencing chronic conditions such as cancer or Acquired Immunodeficiency Syndrome (AIDS). It is considered relevant for managing appetite, as it supports an orexigenic effect that may assist with increasing food intake and is relevant for easing symptoms of malnutrition, supporting the goal of weight maintenance or gain. This provides support that helps ease the overall symptom burden of profound nutritional decline.

“Felipil is applied across domains where additional symptomatic support is needed, primarily focusing on nutritional stability and appetite enhancement. It may assist patients with managing symptom fluctuations.”

Palliative Management of Advanced Hormone-Sensitive Cancers

Felipil is also commonly used in situations involving certain distressing symptoms associated with the progression of specific advanced, recurrent, or metastatic cancers, including breast cancer and endometrial cancer, that are sensitive to hormonal modulation. Used across domains where additional symptomatic support is needed, the medication offers supportive relief that may help patients cope more steadily with symptom fluctuations in the advanced stages of these malignancies. Indications for use include advanced, recurrent, or metastatic breast cancer, advanced endometrial cancer, AIDS-associated cachexia, and anorexia/cachexia in patients with neoplastic disease.


Quick Fact: Symptomatic Support for Nutritional Wasting Felipil plays a role in managing symptoms of severe involuntary weight loss and loss of appetite, assisting with maintaining functional stability during symptomatic periods.

Regulatory References

  1. NIH MedlinePlus overview

Eligibility and Restrictions for Use

Official Regulatory Eligibility for Felipil

Population Group Official Regulatory Status
Contraindicated Known or suspected pregnancy (fetal harm risk); Hypersensitivity to megestrol acetate or formulation components; Co-administration with dofetilide (some labels).
Age Eligibility Approved only for Adult patients (18+). Safety and effectiveness are not established in pediatric patients. Older adults require cautious dose selection due to organ function decline.
Special Restrictions Patients with a history of thromboembolic disease or diabetes mellitus require caution. Caution also advised for impaired renal or hepatic function.
Reproductive Status Use in pregnancy is contraindicated. Nursing mothers must discontinue breastfeeding. Females of reproductive potential must use effective contraception during therapy.

Eligibility Classifications (High-Level)

Classification Regulatory Basis
Contraindicated Absolute prohibition
Not Established Insufficient safety/efficacy data (e.g., Pediatric)
Use with Caution Conditional use required due to risk factors (e.g., Organ impairment, Thromboembolic history)

Official Eligibility Statements

  • Felipil is officially limited to the adult population, as safety and efficacy have not been established in patients under 18 years of age.
  • The medicine is formally contraindicated in women who are pregnant or suspected of being pregnant, and for patients with a documented hypersensitivity.
  • Use requires caution in patients with pre-existing conditions such as diabetes mellitus and a history of thromboembolic events, as defined in official regulatory labeling.

This framework delineates the populations for whom use is permissible, restricted, or prohibited, based strictly on the risk profile and established data documented in government-approved prescribing information.

What should I know about interactions with other medicines?

Felipil Interactions with Other Medicines and Products

This section outlines the officially documented interaction patterns for Felipil (megestrol acetate) as defined by government regulatory authorities.


Documented Exposure-Altering and Pharmacodynamic Interactions

Interactions can influence the levels or effects of co-administered medicines, requiring specific clinical monitoring based on regulatory labeling.

Interacting Substance Official Interaction Pattern Monitoring Requirement
Indinavir (Antiviral) Results in a significant decrease in Indinavir exposure (reduced plasma levels). Consideration of a higher dose of Indinavir is warranted.
Warfarin (Anticoagulant) May increase the effects of Warfarin. Requires close monitoring of the International Normalized Ratio (INR).
Antidiabetic Agents Can cause exacerbation of pre-existing diabetes mellitus, diminishing the drug's therapeutic effect. Requires careful management of the antidiabetic regimen.

Population-Specific Cautions

Due to the medicine's substantial renal excretion, regulatory caution is advised for specific populations:

  • Geriatric Patients: Since older patients are more likely to have reduced kidney function, the official label notes that the risk of toxic reactions may be greater in this population.
  • Patients with Pre-existing Diabetes: The risk of pharmacodynamic interference is heightened due to the official report of exacerbation of pre-existing diabetes.

Mechanism of Action

Felipil, containing megestrol acetate, functions as a synthetic progestin. Its primary molecular target is the progesterone receptor (PR), to which it binds with a non-selective, high-affinity agonist action. This binding occurs within steroid hormone target tissues, including the ovary, uterus, and mammary gland.

Intracellularly, the activated megestrol acetate-PR complex translocates to the nucleus, modifying gene transcription by interacting with specific DNA response elements. In the hypothalamic-pituitary-ovarian axis, this action exerts a central inhibitory feedback effect, resulting in altered concentrations of Gonadotropin-Releasing Hormone (GnRH) and subsequent reduced secretion of the pituitary gonadotropins, Follicle-Stimulating Hormone (FSH) and Luteinizing Hormone (LH).

Downstream, the diminished gonadotropin signaling modulates ovarian steroidogenesis. At the system level, this hormonal suppression leads to an alteration of the female reproductive cycle's regulatory mechanisms. At high concentrations, megestrol acetate also demonstrates an anti-androgenic effect by binding to androgen receptors.

Dosage and Administration Information

How Felipil is Used in Clinical Practice

Felipil (megestrol acetate) is administered exclusively via the oral route, available in both tablet and liquid oral suspension forms. The official usage patterns and required dosing depend strictly on the condition being addressed.


Dosing and Administration Schedules

Administration schedules are defined by the specific formulation and therapeutic context.

Clinical Context Labeled Dosing Regimen Frequency Pattern
Advanced Breast Cancer 160 mg per day Once daily or in 40 mg divided doses
Advanced Endometrial Carcinoma 40 mg to 320 mg per day Typically in divided daily doses
Anorexia/Cachexia (Oral Suspension) 625 mg or 800 mg per day* Once daily

*The dosage for cachexia is dependent on the specific concentration of the oral suspension (e.g., 125 mg/mL vs. 40 mg/mL), making the two liquid strengths non-substitutable.


Procedural Use Requirements

To ensure proper use, the official label includes specific procedural instructions. The oral suspension must be shaken well before each measured dose. For the concentrated suspension (125 mg/mL), administration can occur without regard to meals.

For certain cancer treatments, the labeled protocol specifies that a minimum of two continuous months of daily administration is required to adequately assess the drug’s performance. Furthermore, the single score-line on the 160 mg tablet is intended only to assist with swallowing, not to divide the tablet into half-doses.

Age-Group Guidance: Dose selection for older adults should proceed with caution, often starting at the lower end of the labeled dosing range due to age-related physiological changes. Safety and effectiveness in children have not been established.

Recent Clinical Evidence

Research evidence / Overview of Studies for Felipil

Evidence from Trials for Appetite Loss and Wasting Syndromes

Research has explored the use of Felipil (megestrol acetate) in conditions characterized by severe, involuntary weight loss and poor appetite, medically known as cachexia and anorexia. This research has primarily involved short-term Randomized Controlled Trials (RCTs) and systematic reviews of these trials. Felipil was observed in patient groups experiencing this syndrome, often related to underlying conditions such as cancer and Acquired Immunodeficiency Syndrome (AIDS).

Research examined patient-reported outcomes describing perceived discomfort associated with appetite, alongside changes measured in body weight. Studies reported patterns related to measured changes in appetite and weight that were observed in the group receiving Felipil, relative to the placebo group. This evidence contributes to understanding symptom patterns, but the observed data primarily reflect short-term changes.

What remains unclear is the long-term data regarding the durability of these patterns; long-term effects are not fully established beyond the initial few months of observation. Evidence is limited regarding the specific type of weight change measured—whether it primarily reflects fat or lean muscle mass. Furthermore, the findings were mixed regarding consistent changes in Quality of Life and functional scales used across the different studies, and certainty remains low for these broader outcomes.

Evidence from Studies in Advanced Hormone-Sensitive Cancers

Felipil was also evaluated in patients with advanced or recurrent hormone-sensitive malignancies, notably certain types of breast cancer and endometrial cancer. The research in this area relies on Phase II and III trials that were considered in regulatory assessments, many of which were conducted in earlier decades. Studies explored how this medicine influences cancer-related outcomes related to systemic or functional imbalance, such as measures of tumor response (shrinkage) and time until the cancer progresses again (progression-free survival).

Studies monitored the duration of patient responses and how symptoms evolved in the observed populations. Trials described patterns of tumor stabilization or reduction in some specific patient groups, and the evidence contributes to the broader research landscape for palliative hormonal therapy.

Comparative evidence is lacking regarding how this medicine performs against many contemporary available hormonal or targeted therapies used today. Furthermore, the results apply only to the specific populations studied, and subgroup findings are uncertain concerning which patients are most likely to show a response in the context of current treatment protocols. Research is ongoing to better define the specific markers that might indicate which patients may be most appropriate for this approach.

Long-Term Research and Durability of Study Outcomes

Research has primarily focused on studies observing responses over defined time intervals, meaning that follow-up durations were limited in many of the key effectiveness trials, particularly those concerning appetite loss. There is limited information for long-term outcomes on the sustained maintenance of measured weight and appetite improvements over periods longer than 3–4 months. Research provides context about group patterns, but not individual predictions about how long any observed changes may last. This lack of established long-term data highlights a key area where more comprehensive research is needed.

Evidence in Specific Patient Populations

Felipil was evaluated in specific patient populations, including Adults with AIDS-related weight loss and Adults with various cancer types. Research has also explored its use in older adults facing nutritional decline. However, data for certain groups remain insufficient. For example, limited information for long-term outcomes is available for a full range of pediatric (child) cancer-related weight loss in the official regulatory evidence. Findings describe group patterns, not personal outcomes, and the evidence base for special populations, particularly those with multiple severe comorbidities, is limited.

What Research is Still Uncertain About Felipil

Evidence highlights what is known—and what is still uncertain. Evidence quality varies across studies, with some older trials having limitations in their design or reporting methods. Sample sizes were modest in some of the foundational studies, which can reduce the certainty of findings. The evidence suggests that a key area of uncertainty involves the variability in patient response and how to identify, before treatment begins, which individuals may experience the most noticeable measured changes. Comparative evidence is lacking against many modern pharmacological interventions currently used for both cancer control and nutritional support. The research provides insight into short-term changes, but research is ongoing to resolve these remaining gaps.

Key Studies & References

  1. Megestrol acetate for the treatment of anorexia-cachexia syndrome: a systematic review and meta-analysis
  2. Megestrol acetate for breast cancer: an international review of its efficacy and safety
  3. Supportive Care Guidelines: Use of Megestrol Acetate for Cachexia in Cancer Patients (Reference to Major Oncology Society Guidelines, e.g., ASCO/NCCN)

Frequently Asked Questions (FAQ)

Common questions about Felipil (FAQ)

Q: How is the 'How Felipil works' description generally compared to other drugs for the same condition?

Official documents state that Felipil is a synthetic progestin and is described as interfering with the activity of the estrogen hormone. This interference is known as an antiestrogenic property. However, the precise way the medicine stimulates appetite and contributes to weight gain is not yet fully understood or established in official texts.

Q: Does Felipil treat the underlying cause of the condition or primarily the symptoms?

The medicine is prescribed to manage specific advanced conditions and associated symptoms, such as severe, involuntary weight loss. Official regulatory information indicates that therapy is generally reserved until after other treatable underlying causes of the condition, like systemic infections or disorders, have been sought.

Q: Can Felipil potentially cause long-term side effects that may only appear after years of use?

The official label reports cases of two serious conditions—overt Cushing’s Syndrome and adrenal insufficiency—that have been reported in association with extended use of the active ingredient. These warnings are included in the product information to inform about potential long-term safety considerations.

Q: What are the typical signs of a possible allergic reaction to Felipil?

Symptoms that are described in patient information include the development of a rash, hives, or swelling of the face or throat. Other signs noted are dizziness and any difficulty with breathing. These symptoms are officially noted in patient information as requiring prompt medical attention.

Q: Are the reported side effects of Felipil different for older adults compared to younger adults?

Regulatory documents advise that dose selection for older adults should be approached with caution. This caution reflects the general concern for the increased potential for age-related decline in organ function. The information does not, however, specify that the adverse event profile itself is generally different compared to younger adult patients.

Q: What is the importance of maintaining a consistent and accurate list of all current medications when starting Felipil?

The importance of a complete medication list is highlighted by the official warnings regarding potential drug-drug interactions. Felipil is known to interact seriously with certain other medicines, such as the anticoagulant Warfarin and the antiviral Indinavir. Such interactions can necessitate professional monitoring or dose adjustments.

Q: Does the official documentation mention any potential for dependence or withdrawal symptoms with Felipil?

The official documentation reports that adrenal insufficiency has been reported in patients after they stop chronic use of the active ingredient. Symptoms of this insufficiency may include hypotension, weakness, nausea, vomiting, and dizziness. This warning is included to guide management during discontinuation.

Q: Is Felipil the brand name or the generic name for the active ingredient?

Felipil is the proprietary brand name designated for this pharmaceutical product. The active ingredient contained within this medicine is the generic substance known as megestrol acetate.

Q: Are there non-drug alternatives or lifestyle changes commonly studied alongside Felipil treatment?

The regulatory label addresses underlying health issues related to the condition. Official information indicates that therapy is generally reserved until after other treatable causes of weight loss, such as systemic infections or disorders, have been identified.

Q: Is Felipil generally described as a short-term or long-term medication?

The official indications for this medicine involve the palliative treatment of advanced conditions. The required assessment period indicates that effects are evaluated after a minimum period of two continuous months.

Q: How soon can a person typically expect to notice any initial effects from taking Felipil?

Official pharmacokinetic data describes the absorption rate of the medicine. Depending on the specific formulation used (tablet or oral suspension), this measurement reflects when the concentration of the medicine in the bloodstream is highest, which occurs between one to five hours after administration.

Q: Is a warning about drowsiness or impaired driving ability officially listed on the Felipil label?

While the label does not explicitly list 'drowsiness,' the adverse reaction lists include central nervous system (CNS) effects. These CNS effects include lethargy, confusion, and abnormal thinking. These effects may be associated with changes in mental status.

Q: How is the liver generally monitored during treatment with Felipil, according to regulatory guidelines?

Official regulatory guidelines for the active ingredient indicate that liver function should be checked when starting treatment. Regulatory information specifies that liver function tests should be conducted at baseline and subsequently monitored.

Q: Does the official labeling mention interactions with common herbal supplements or vitamins?

Official information has documented minor interactions with certain substances, such as a substance derived from the Maitake mushroom. Regulatory interaction checkers classify these effects as either minor or of unknown clinical significance at this time.

Q: Are there any known drug-drug interactions with Felipil that are clinically insignificant and do not require action?

Regulatory interaction databases do classify some drug combinations involving Felipil as having a 'Minor' clinical significance. These findings indicate that while an interaction is known to occur, they are generally not expected to require changes to a dose.

Q: Is there a specific Consumer Medicine Information (CMI) or patient information leaflet (PIL) available for Felipil?

The regulatory label includes a dedicated section on Patient Counseling Information. This section provides necessary non-clinical guidance and key safety information required for patients using the medicine.

Q: What official government or intergovernmental resources are available for patients who want more factual information about Felipil?

Patients can access information from authoritative government resources. These include national bodies like the National Cancer Institute (NCI) and regulatory programs such as the FDA’s MedWatch program for reporting adverse events.

How should Felipil be stored and disposed of?

How to Store and Dispose of Felipil?

The storage and disposal of Felipil (megestrol acetate) must adhere to the official conditions defined in the regulatory labeling.


Required Storage Conditions

Felipil must be stored at 25 C (77 F), with permitted excursions between 15 to 30 C (59 to 86 F). It is a requirement to keep the product from freezing and protect it from temperatures above 40 C (104 F). The tablet formulation must be stored in the original package to protect it from moisture. The oral suspension must be kept in a tight container and requires shaking well before use. The medicine must be stored out of the sight and reach of children.


Disposal Instructions

Unused or expired Felipil must be properly disposed of and not kept. Disposal of both the contents and the container must be carried out in accordance with all local, regional, national, and international regulations, as megestrol acetate is classified as a hazardous substance.

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

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