Femilon

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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 Femilon

Quick Facts

Property Description
Active ingredient Desogestrel, Ethinyl Estradiol
Form Oral Tablet
Pharmacological class Hormonal Contraceptive (COC)
Common use Prevention of pregnancy
Origin Synthetic Hormones

What is Femilon?

What Type of Medicine is Femilon?

Femilon is a prescription-only Combined Oral Contraceptive (COC) tablet that belongs to the broader Hormonal Contraceptive class of medicines. This preparation is a fixed-dose combination product designed for oral administration, a delivery method clinically recognized for its high degree of patient adherence and reliable systemic effect. The established classification as a COC reflects its status as an efficacious method of contraception, relying on the consistent delivery of synthetic steroid hormones. The use of this combination formulation is confirmed to be an established, effective option for women seeking to manage their reproductive health.

The medicinal entity is chemically designed to provide a steady supply of these hormones over a cycle, specifically targeted at adult and post-menarche female patient groups. It is categorized by its route of administration as an oral dosage form, meaning it is manufactured as a solid unit ingested through the mouth. The structure of the formulation is intentionally simplistic, delivering a consistent level of the active substances in every active tablet, which supports reliable patient compliance.

Composition of Femilon: Synthetic Progestin and Estrogen

The primary efficacy of the pill is rooted in its two active ingredients: Desogestrel and Ethinyl Estradiol. Desogestrel is the progestin component, a third-generation synthetic progestin derivative, while Ethinyl Estradiol serves as the synthetic estrogen. Pharmacological studies have supported the hormonal potency of Desogestrel, contributing to the formulation's overall effectiveness. Both compounds are chemically synthesized substances, ensuring precise, measurable hormonal action within the body, unlike naturally sourced hormone products.

This combination of an estrogen and a progestin is critical, as the two hormones work synergistically to provide comprehensive suppression of reproductive function. The final product is a tablet formulated with these active compounds alongside solid pharmaceutical excipients necessary for stability and absorption, which constitutes its high-level composition.

General Purpose of the Combination Pill

The overarching objective of using this medication is highly effective contraception, which involves the prevention of pregnancy. By introducing steady levels of Desogestrel and Ethinyl Estradiol, the pill modulates the body's reproductive cycle to temporarily suspend the conditions necessary for conception. A typical use scenario involves a woman seeking highly dependable, reversible birth control that does not rely on actions taken at the time of intercourse.

Beyond its primary contraceptive role, the consistent administration of this hormone combination often leads to predictable cycle management. Many users experience the secondary benefit of promoting regularity in their menstrual cycles and reducing the variability of symptoms commonly associated with the natural cycle.

Regulatory References

  1. Birth control pills - combination

What side effects are possible with Femilon?

Femilon (desogestrel and ethinyl estradiol) is a combined oral contraceptive that, like all medications, can cause side effects. Most common side effects are typically mild and often improve after the first few months of use as the body adjusts to the hormones.

Common Side Effects

System/Area Common Effects
Gastrointestinal Nausea, vomiting, abdominal pain
Breasts Tenderness, pain, or enlargement
Nervous System Headache, dizziness, mood changes (including depression)
General Weight changes (gain or loss), fluid retention (edema)
Menstrual Spotting or breakthrough bleeding (bleeding between periods), changes in menstrual flow, missed periods

Serious Safety Information

Femilon may increase the risk of serious but rare side effects, most notably the formation of blood clots (thrombosis) in the veins (Deep Vein Thrombosis/Pulmonary Embolism) or arteries (heart attack, stroke). The risk is highest during the first year of use and is further increased by factors such as smoking (especially over age 35), obesity, uncontrolled high blood pressure, and certain hereditary conditions.

Seek immediate medical attention if you experience signs of a blood clot, such as:

  • Sudden, severe chest pain or shortness of breath
  • Unusual pain, swelling, or warmth in one leg
  • Sudden severe headache or vision changes

Femilon is generally contraindicated in women with a history of certain conditions, including blood clotting disorders, uncontrolled high blood pressure, certain cancers (like breast cancer), liver disease, and severe migraine headaches with aura. Patients who are pregnant or breastfeeding should not use this medication.

Overdose and Emergency Response

Overdose and When to Seek Help

Official regulatory information for Femilon (Desogestrel/Ethinyl Estradiol) overdose emphasizes that the acute toxicity is generally low. Overdose is not expected to cause life-threatening complications or serious harmful effects.

Documented Overdose Manifestations

Symptoms reported following the ingestion of a large dose are typically mild and limited to the following:

  • Nausea
  • Vomiting
  • Vaginal bleeding (specifically, withdrawal bleeding or slight bleeding)

In young girls who have not yet reached puberty (pre-menarche), slight vaginal bleeding may occur as a specific manifestation of overdose.

Emergency Action and Management

When to seek help: If an overdose is suspected, immediate medical attention should be sought by calling emergency services or a poison control center.

Management: Official guidance confirms that no specific antidote is available for this combination of hormones. Therefore, management of an overdose is primarily symptomatic and supportive. Healthcare providers may administer supportive care and monitor vital signs. Gut decontamination measures, such as the use of activated charcoal, may be considered in certain acute poisoning scenarios.

Therapeutic Uses of Femilon

The primary purpose of this medication is the prevention of pregnancy. This medication is commonly used to help with multiple therapeutic areas, applied across domains where additional symptomatic support is needed. This class of medication is also applied to address several other conditions and symptom clusters.

Contraception, Cycle Control, and Symptom Relief

Femilon is commonly used to help with reproductive health management, providing a continuous method for family planning, while contributing to improved comfort during periods of heightened symptoms by being used for managing irregular menstrual cycles. The medication is relevant for easing symptoms related to physical discomfort, particularly symptoms that interfere with daily functioning, such as menstrual cramping (dysmenorrhea) and excessive menstrual bleeding (menorrhagia). It helps address symptom clusters that may become intense or disruptive, providing supportive relief for managing challenging symptoms.

Femilon is also considered relevant for easing symptoms related to heightened physiological activity, specifically in managing the dermatological manifestations of persistent acne. Consistent use of this medication may be part of symptomatic management associated with long-term benefits, such as assisting with risk mitigation for developing certain cancers.

“This medication is commonly used across conditions presenting with episodic or fluctuating symptom patterns, offering supportive relief for managing challenging symptoms.”


Quick Fact: Relief for Symptomatic Manifestations Therapeutic Focus Conditions and Symptoms Managed
Reproductive Management Prevention of pregnancy, irregular periods
Menstrual Symptoms Severe cramping, excessive bleeding
Dermatological Symptoms Persistent acne
Long-Term Benefits Assistance with cancer risk mitigation

Eligibility and Restrictions for Use

Femilon is an oral contraceptive pill indicated for use by females of reproductive potential to prevent pregnancy. Eligibility for use is strictly determined by a woman's current and past health status, with specific conditions establishing absolute contraindications.

Populations Who Must Not Use Femilon (Contraindications)

Official regulatory documents state that this medicine is contraindicated in individuals with the following health conditions or risk factors, primarily due to the increased risk of serious adverse events:

  • Thromboembolic/Vascular Risk: A high risk of arterial or venous thrombotic diseases, including a history of deep vein thrombosis, pulmonary embolism, stroke, or heart attack. This risk is notably increased and therefore contraindicated in women over age 35 who smoke.
  • Hormone-Sensitive Neoplasia: Known or suspected breast cancer or other cancers sensitive to estrogen or progestin.
  • Hepatic/Liver Function: Current or history of liver tumors, acute viral hepatitis, or decompensated cirrhosis (severe liver disease).
  • Gastrointestinal/Renal: Renal impairment or adrenal insufficiency.
  • Bleeding/Pregnancy Status: Undiagnosed abnormal uterine bleeding or known/suspected pregnancy.

Eligibility-Related Restrictions

Use is not recommended in women who are breastfeeding, as the hormones can decrease milk production. Furthermore, the medicine must not be started until at least four weeks after delivery in women who are not breastfeeding, due to elevated thromboembolic risk during this time.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Interactions with Femilon (Desogestrel/Ethinyl Estradiol) are primarily defined by documented changes in hormone plasma concentrations and pharmacodynamic risk synergism, as specified in regulatory labeling. The product is subject to both pharmacokinetic and pharmacodynamic interactions.


Official Interaction Statements

Classification Interacting Agents (Examples) Documented Outcome/Restriction
Contraindicated Combinations Fezolinetant, Cigarette Smoking (gt 35 years) Ethinyl Estradiol increases Fezolinetant exposure via CYP1A2 inhibition; Smoking poses a synergistic cardiovascular risk.
Reduced Efficacy Risk Rifampicin, Anticonvulsants (e.g., Phenytoin), St. John's Wort Enzyme inducers increase hormone clearance, which is officially documented to lead to reduced contraceptive efficacy.
Increased Drug Exposure CYP1A2 Substrates (e.g., Tizanidine, Caffeine) Ethinyl Estradiol is documented as a CYP1A2 inhibitor, resulting in increased plasma concentrations of these co-administered drugs.

Procedural Constraints

The medication must be discontinued at least four weeks prior to and for two weeks after elective surgery associated with an increased risk of thromboembolism. Females over 35 years of age who smoke face a heightened interaction risk that classifies the combination as a contraindication in this specific population.

Mechanism of Action

The mechanism of this fixed-dose combination product is based on the simultaneous action of its two synthetic hormones, Ethinyl Estradiol and the active progestin metabolite, Etonogestrel, engaging three primary physiological blockades.

Central Suppression of the HPO Axis

This is the primary physiological mechanism, driven by the continuous agonism of Etonogestrel at the Progesterone Receptor and Ethinyl Estradiol at the Estrogen Receptor. This steady signaling induces a profound negative feedback signal to the hypothalamus and pituitary. The systemic consequence is the suppression of FSH and the crucial LH surge, which establishes the physiological state of anovulation (the absence of egg release).

Creation of Peripheral Biophysical Barriers

Beyond central control, the progestin component modifies the lower reproductive tract. Continuous receptor activation leads to a significant increase in the viscosity of cervical mucus, creating a thick, physical, and chemical barrier that impedes sperm movement. Furthermore, the mechanism alters the endometrium, rendering the tissue unreceptive for implantation should an escape ovulation occur.

Mechanistic Synergy and Threshold Control

The fixed-dose combination ensures the synergy between the two hormones, where the estrogen reinforces the progestin's central antigonadotropic effect, leading to a sustained suppression of the HPO axis. The entire mechanism is threshold-dependent, requiring hormone concentrations to remain above a critical plasma level to sustain the peripheral barrier effects.

Dosage and Administration Information

Official Administration Guidelines for Femilon

Femilon (desogestrel/ethinyl estradiol) is administered orally via a fixed, cyclic 28-day regimen. Strict adherence to the official dosing schedule and timing is essential for maintaining effectiveness.


Administration Scope Procedural Requirements
Route of Administration Oral (tablet is swallowed whole).
Dosing Schedule One active tablet daily for 21 consecutive days, followed by a 7-day pill-free interval (or 7 days of an inactive/placebo tablet).
Timing & Frequency Take one tablet at the same time every day. The maximum interval between doses must not exceed 24 hours.
Start Procedures The first tablet can be started on the first day of the menstrual period (Day 1 Start) or on the first Sunday after the period begins (Sunday Start). Starting on the Sunday Start requires the use of additional non-hormonal contraception (e.g., condom) for the first 7 days.

Missed Dose Instructions

Missed dose instructions depend on the time elapsed since the scheduled dose. If an active tablet is missed, follow these rules, which prioritize maintaining the daily hormone exposure:

  • Less than 12 hours late: Take the missed tablet immediately. The contraceptive protection is maintained, and subsequent tablets should be taken at the usual time.
  • More than 12 hours late: Take the missed tablet immediately (taking two tablets in one day is permitted). Additional barrier contraception (e.g., condoms) must be used for the next 7 consecutive days. The risk of pregnancy is highest if tablets are missed near the beginning or end of the 21-day active tablet cycle.

If severe vomiting or diarrhea occurs within 3 to 4 hours of taking an active tablet, the absorption may be incomplete; this should be treated as a missed dose, and a new active tablet should be taken as soon as possible.

Recent Clinical Evidence

Femilon: Recent Clinical Evidence

Clinical evidence for Femilon (a combination of desogestrel and ethinyl estradiol) primarily focuses on its established use as a combined oral contraceptive (COC). Research studies consistently confirm its role in the prevention of pregnancy.

Contraceptive Efficacy

Combined hormonal contraceptives are studied using the Pearl Index, which measures the number of pregnancies per 100 woman-years of use. Clinical trials evaluating the desogestrel/ethinyl estradiol combination report a high user-efficacy rate, often below 1 pregnancy per 100 woman-years when taken consistently as directed. The primary mechanism of action involves the inhibition of ovulation, supplemented by changes to the cervical mucus (impeding sperm) and the endometrium (reducing implantation likelihood).

Secondary Benefits and Tolerability

Studies also investigate non-contraceptive effects. For some users, this combination may be associated with improved menstrual cycle regularity and a reduction in both the amount and duration of withdrawal bleeding during consecutive treatment cycles. This finding supports its use in the management of conditions such as heavy menstrual bleeding (HMB) for certain women.

Area of Research Key Study Findings
Cycle Control Reported decreases in the duration and amount of withdrawal bleeding
Adverse Events Incidence of minor side effects (e.g., nausea, headache) generally low and often decreasing with prolonged use

Serious risks, such as venous thromboembolism (VTE), are a known, albeit small, risk associated with all combined oral contraceptives and are routinely monitored in clinical safety assessments. The benefit-risk profile is carefully evaluated for each individual by healthcare providers, particularly considering risk factors such as smoking and age.

Frequently Asked Questions (FAQ)

Common questions about Femilon (FAQ)

Q: If I miss two or more active pills, what specific steps should I take to continue the cycle and maintain protection?

Instructions for missing two or more active tablets are detailed in the official product information and are based on the week the pills were missed. This situation requires specific actions, as detailed in the official patient information. Regulatory documents indicate that the use of additional non-hormonal contraception, such as a barrier method, may be required for seven days, and the plan may involve adjusting the inactive pill interval.


Q: Can Femilon be used to help manage heavy or irregular menstrual bleeding, and if so, what is the mechanism?

While Femilon's primary purpose is contraception, official information indicates that combined oral contraceptives may also be used to help manage painful periods (dysmenorrhea) and promote cycle regularity. This effect is related to the hormonal components controlling the uterine lining and bleeding pattern. Clinical studies have reported a reduction in the amount and duration of withdrawal bleeding for some users.


Q: Is it necessary to take a pill-free break after I complete my first year of Femilon, or can I take the active pills continuously to skip my period?

The standard administration schedule for Femilon is the 28-day cyclic regimen, which includes a 7-day pill-free or inactive interval. Taking the active tablets continuously to skip the withdrawal bleed is a recognized alternative regimen, though it is not the officially labeled method. Users interested in changing their bleeding pattern should refer to the full regulatory labeling or consult a healthcare professional for guidance.


Q: How soon after stopping Femilon can I expect my fertility to return, and are there any factors that influence this timeline?

Official information and studies on combined oral contraceptives suggest that the return to fertility typically occurs relatively quickly after the medication is stopped. Ovulation and the return to fertility typically occur relatively quickly after the medication is stopped, often within several months. The use of the pill itself is not associated with a long-term reduction in the ability to become pregnant.


Q: What are the signs or symptoms of the serious, but rare, blood clot risk (VTE) that require immediate medical attention?

Signs of a serious blood clot (thrombosis) that require immediate medical attention are listed in the official safety information. These symptoms may include sudden, severe chest pain; sudden shortness of breath; unusual pain, swelling, or warmth in one leg; or a sudden, severe headache or vision changes. Seeking immediate medical attention is advised in the official safety guidance if any of these symptoms are present.

How should Femilon be stored and disposed of?

How to Store and Dispose of Femilon?

Femilon tablets must be stored according to official regulatory specifications to maintain their stability and effectiveness. The medicine must be stored at a temperature below 25°C or below 30°C, depending on the regional label. To protect the active ingredients, the tablets must remain in the original package to shield them from both light and moisture. For safety, the product must be kept out of the sight and reach of children.

Disposal Requirements

Femilon should not be disposed of via wastewater or routine household waste. Any unused or expired medicine must be discarded in accordance with local requirements for pharmaceutical waste, which often involves returning it to a pharmacy or designated collection program. The tablets must not be used past the expiry date printed on the packaging.

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

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