Cilest

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Cilest

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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 Cilest

Property Description
Active ingredients Ethinyl Estradiol, Norgestimate
Form Oral Tablet (Pill)
Pharmacological Class Hormonal Contraceptive Agent, Combined Oral Contraceptive (COC)
Primary Use Prevention of Pregnancy (Systemic Contraception)
Origin Synthetic Hormonal Preparation

Cilest is a prescription-only Combined Oral Contraceptive (COC) used for systemic contraception (birth control). This oral tablet is classified as a hormonal contraceptive agent, combining two types of synthetic hormones to prevent pregnancy in women of childbearing potential. The combination of Ethinyl Estradiol and Norgestimate is used as a means of reversible birth control.

Defining Cilest: Type and Pharmacological Class

Cilest falls under the broad pharmacological classification of a Hormonal Contraceptive Agent. The product is a Combined Oral Contraceptive (COC) pill because its active component comprises both a synthetic estrogen and a synthetic progestin. This dual-hormone approach provides systemic contraception, offering a different mechanism balance compared to Progestin-Only Pills.

Composition: Ethinyl Estradiol and Norgestimate

Its active ingredients are the estrogenic compound Ethinyl Estradiol (EE) and the progestational compound Norgestimate (NGM). Norgestimate is a third-generation progestin. This classification is a key differentiating factor, as third-generation progestins are associated with having minimal intrinsic androgenic activity. The combination of these specific synthetic hormones in the tablet form facilitates the primary high-level mechanisms: the inhibition of ovulation and the creation of barriers to fertilization and implantation.

General Contraceptive Purpose

The overarching purpose of Cilest is to interrupt the reproductive cycle to provide contraception. The synthetic hormones work by primarily suppressing the hormones needed for ovulation, which prevents the monthly release of an egg from the ovary. Concurrently, the progestin component also causes the cervical mucus to thicken, which physically impedes sperm transit, thus contributing to the drug's goal of pregnancy prevention.

Regulatory References

  1. FDA Drug Label for Norgestimate/Ethinyl Estradiol
  2. WHO Essential Medicines List for Contraceptives
  3. NIH StatPearls on Progestins

What side effects are possible with Cilest?

Possible side effects and safety information

The safety profile for this combined oral contraceptive, containing Norgestimate and Ethinyl Estradiol, is derived from official government regulatory documents (e.g., FDA and EMA labels) and is structured by the frequency and physiological system affected.


Frequency-Classified Adverse Reactions

Adverse reactions are formally categorized to communicate their expected incidence:

  • Common (ge 1/100): Officially documented reactions frequently reported include headache, nausea, breast pain or tenderness, abdominal pain, mood changes (including depression), weight change, and breakthrough bleeding or spotting.
  • Uncommon/Rare (le 1/1,000): Less frequent but documented events include hypertension (high blood pressure), migraine, and thromboembolic events.

Serious Safety Considerations

Official prescribing information highlights rare but clinically significant reactions, primarily involving the vascular system and liver function:

  • Thromboembolic Events: The risk of Venous Thromboembolism (VTE) and Arterial Thromboembolism (ATE) (e.g., stroke and myocardial infarction) is a serious concern, though classified as rare.
  • Hepatobiliary Disorders: The development of hepatic tumors (adenomas/carcinomas) and gallbladder disease is documented as a rare, serious risk.

Time and Population-Specific Safety Patterns

Regulatory documents specify distinct risk patterns related to exposure and patient characteristics:

  • Time-Related Risk: The risk of VTE is officially documented as being highest during the first year of use.
  • High-Risk Population: The risk of serious cardiovascular adverse reactions, particularly stroke and myocardial infarction, is significantly increased for females over 35 years of age who smoke.

Safety-Related Restrictions

Use is formally restricted (contraindicated) in the presence of certain medical conditions, including a history of thrombotic disease, known or suspected breast cancer, liver tumors, or active liver disease.

Overdose and Emergency Response

Overdose and When to Seek Help

The official regulatory profile for an acute overdose of Cilest (Norgestimate and Ethinyl Estradiol) classifies the event as having low acute toxicity, and a serious or life-threatening outcome is not expected.

Overdose Classifications (Official Regulatory Basis) Statement
Severity Classification Low toxicity; not expected to be serious or life-threatening.
Antidote Availability No specific antidote is known.

Documented Overdose Presentations and Required Actions

Overdose manifestations are typically limited to nausea, vomiting, and the occurrence of withdrawal bleeding (or vaginal bleeding). This bleeding manifestation may occur even in females prior to menarche (the start of menstruation).

Because no specific antidote is known, management must be purely symptomatic and supportive.

Immediate medical attention is required upon suspicion of an overdose to ensure appropriate monitoring. Regulators mandate contacting a Poison Control Center immediately for guidance. Individuals should call emergency services immediately if severe symptoms, such as collapse or difficulty breathing, are observed. The required supportive care focuses on treating the clinical signs presented.

Therapeutic Uses of Cilest

The combined hormonal composition of Cilest generally supports the patient across key therapeutic domains, focusing on support for cycle regularity and symptomatic relief for specific conditions in females of reproductive potential.

The core therapeutic domain is primarily relevant for managing the risk of unintended pregnancy. The medication is applied in addressing the need for reversible pregnancy prevention (systemic contraception) and assists with long-term family planning goals. It is relevant for easing the symptom intensity of dysmenorrhea (severe menstrual cramps), menorrhagia (excessive blood loss), and to address manifestations of moderate acne.

This application contributes to a sense of stability regarding the risk of unintended pregnancy and may contribute to lighter, less painful, and more predictable periods.

“A significant benefit of this medication is providing sustained support during periods of heightened symptoms associated with the menstrual cycle and related conditions.”

Quick Fact: Relief for Menstrual Distress The medication helps address groups of symptoms that create noticeable interference with daily stability, particularly those related to severe cramping and heavy bleeding, supporting patients during difficult symptomatic phases.

Regulatory References

  1. NIH DailyMed/FDA Label on Norgestimate and Ethinyl Estradiol

Eligibility and Restrictions for Use

Cilest is a Combined Oral Contraceptive (COC) for use in females of reproductive potential to prevent pregnancy. Eligibility is strictly defined by regulatory authorities based on a patient's age and the presence of specific contraindicating health conditions.

Populations and Conditions Prohibited from Use

Cilest is absolutely contraindicated (must not be used) in patients with the following conditions, as stated in official regulatory labeling:

  • Women over 35 years old who smoke.
  • A high risk of arterial or venous thrombotic diseases (e.g., history of Deep Vein Thrombosis, stroke, or heart attack).
  • Liver tumors (benign or malignant) or active/severe liver disease.
  • Known or suspected breast cancer or other hormone-sensitive malignancy.
  • Undiagnosed abnormal uterine bleeding.
  • Migraine with focal aura or severe, uncontrolled hypertension.
  • Severe diabetes mellitus with vascular involvement.

Conditional Use and Life Stage Restrictions

Use is not indicated for geriatric or postmenopausal women, as safety and efficacy have not been established. The medicine is contraindicated during pregnancy and not recommended during breastfeeding. Postpartum use must be deferred for at least four weeks in non-nursing mothers.

What should I know about interactions with other medicines?

Cilest Interactions with other medicines and products

The interaction profile for Cilest, a Combined Oral Contraceptive (COC), is predominantly defined by pharmacokinetic (PK) changes that affect the plasma concentrations of its active components, Ethinyl Estradiol and Norgestimate. All documented interactions are based on formal regulatory assessments, focusing on metabolism and absorption.


Formal Contraindications and Restrictions

Co-administration with specific Hepatitis C medication regimens containing ombitasvir/paritaprevir/ritonavir, with or without dasabuvir, is formally prohibited due to the risk of elevated liver enzyme levels. The combination of Cilest with cigarette smoking in women over 35 years of age is also a strict contraindication due to a significantly increased risk of serious cardiovascular events. Products containing the herbal supplement St. John’s wort are restricted because they may decrease the contraceptive's effectiveness.


Exposure-Altering Interactions

The most frequent interaction pattern involves the hepatic CYP3A4 enzyme system. Drugs classified as strong CYP3A4 inducers, such as certain anticonvulsants (e.g., phenytoin, carbamazepine) and antimycobacterials (e.g., rifampicin), may decrease the exposure to the COC hormones, risking contraceptive failure. Conversely, strong CYP3A4 inhibitors (e.g., ketoconazole, fluconazole) and Grapefruit juice may increase the plasma concentrations of the hormone components. Co-administration with certain statins (e.g., atorvastatin) is also documented to increase Ethinyl Estradiol exposure.


Timing and Transporter Rules

The bile acid sequestrant Colesevelam is documented to significantly decrease the AUC of Ethinyl Estradiol through a binding mechanism. To mitigate this effect, regulatory guidelines require that Cilest and Colesevelam doses be separated by 4 hours during administration.

Mechanism of Action

Cilest is a combination oral contraceptive containing the progestin norgestimate and the estrogen ethinylestradiol. Its mechanism of action involves three primary biological pathways.

First, the steroid hormones exert a negative feedback effect on the hypothalamic-pituitary-ovarian (HPO) axis. This central action suppresses the release of gonadotropins—specifically, luteinizing hormone (LH) and follicle-stimulating hormone (FSH)—from the anterior pituitary gland. The resultant low levels of gonadotropins inhibit the follicular development and the mid-cycle LH surge necessary for the ovarian process of ovulation.

Second, the progestin component, acting via its active metabolite norelgestromin, modifies the biophysical properties of the cervical mucus. This modification involves an increase in the mucus's viscosity and thickness, creating an altered physicochemical environment that impedes the transit of sperm through the cervical canal.

Third, the combination of steroids induces changes in the endometrium (uterine lining), rendering it less receptive to the implantation of a fertilized ovum. This multi-pathway modulation constitutes the biological mechanism of the drug.

Dosage and Administration Information

Cilest is a combined oral contraceptive pill that contains the active ingredients norgestimate and ethinyl estradiol. It is a 21-day pill, meaning you take one tablet daily for 21 consecutive days, followed by a 7-day pill-free interval.

Starting Cilest

  • Day 1 Start: To be protected immediately, begin taking the first tablet on the first day of your menstrual period. No additional barrier contraception is required when starting this way.
  • Later Start: You may also start on days 2–5 of your period, but you must use a reliable non-hormonal barrier method (like a condom) for the first 7 days of taking the tablets to ensure contraceptive protection.

Daily Administration

Take one tablet at the same time every day, following the order indicated on the blister pack. It can be taken with or without food. Maximum effectiveness is achieved when no more than 24 hours pass between doses.

Cycle Phase Duration Action
Pill-Taking 21 days Take one active tablet daily.
Pill-Free 7 days Take no tablets. A withdrawal bleed (period-like bleeding) will typically occur during this time.

Start the next pack of 21 tablets immediately after the 7-day pill-free interval, even if the withdrawal bleed has not stopped. The new pack should always start on the same day of the week as the first pack.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Cilest

Evidence for Use in Pregnancy Prevention (Systemic Contraception)

The primary research base for this medication includes large-scale Randomized Controlled Trials (RCTs) and long-term observational studies. Research examined the use of the ethinyl estradiol/norgestimate combination in healthy women of reproductive age. These regulatory trials were designed to examine a primary outcome related to the rate of pregnancy occurrences during the defined study intervals. This measurement, often expressed as the Pearl Index, provides context for the patterns observed with the combination in controlled settings.

Studies also monitored secondary outcomes, such as the consistency and duration of menstrual cycles. Research so far indicates group patterns related to outcomes measured for the primary indication in the populations examined under the specific conditions of the study protocols. What remains uncertain is the degree to which trial results translate precisely to daily life, as effectiveness is highly subject to user adherence (patient compliance with the required regimen).


Evidence for Non-Contraceptive Applications

Research has explored outcomes observed in populations with conditions characterized by acute or disruptive episodes, specifically focusing on Dysmenorrhea (severe menstrual cramps) and Menorrhagia (excessive blood loss). These trials monitored patient-reported outcomes describing perceived discomfort and quantified changes in menstrual blood loss.

Evidence for these applications is often derived from RCTs and systematic reviews of the Combined Oral Contraceptive (COC) class and is characterized as having a moderate level of evidence in the research record. Findings described patterns observed in the studies related to measured changes in the severity and duration of bleeding and pain compared to baseline or placebo, but these findings do not determine whether an individual will respond similarly.


Key Research Gaps and Uncertainties

Long-term outcomes, such as the duration of observed measured changes after many years of use, are primarily gathered through ongoing, large-scale observational settings. Long-term outcomes are not fully established through controlled trials. Subgroup findings are uncertain or remain insufficient for specific populations who may not have been widely represented in the original trials, such as those with certain comorbidities.

Key Studies & References NORGESTIMATE AND ETHINYL ESTRADIOL kit (DailyMed - NIH)

Frequently Asked Questions (FAQ)

Common questions about Cilest (FAQ)

Q: Is Cilest considered a 'monophasic' or 'triphasic' pill?

Cilest is a combined oral contraceptive that is officially classified and prescribed as a triphasic regimen. This means the dosage of the active hormones in the tablets changes in three steps across the 21 days of active use. This design is detailed in the official product information.

Q: How quickly is Cilest expected to start working for its intended purpose?

Contraceptive protection is indicated immediately if the first tablet is started on the first day of the menstrual period. According to official guidelines, if the start is delayed to days 2 through 5, a non-hormonal barrier method is documented as being necessary for the first 7 days of tablet taking to ensure contraceptive effectiveness.

Q: How long does the body take to adjust to Cilest?

While the highest risk for serious vascular events is officially documented to be in the first year of use, many common, temporary side effects, such as breakthrough bleeding or nausea, are often noted in official documents to improve within the first few cycles (typically the first three months) as the body adjusts to the hormone components. Side effects such as these are often temporary.

Q: Is it common to have spotting or breakthrough bleeding when starting Cilest?

Yes, breakthrough bleeding or spotting (unscheduled bleeding) is classified as a Common adverse reaction in the official product information. It is often reported during the initial cycles as the body adjusts to the hormones. This unscheduled bleeding is often temporary.

Q: What is the difference between breakthrough bleeding and a regular bleed on Cilest?

According to official documentation, breakthrough bleeding or spotting is defined as unscheduled bleeding that occurs during the 21 days when you are taking the active hormone tablets. The regular bleed is the expected withdrawal bleed that typically occurs during the pill-free week.

Q: What is the main role of the progestin component in Cilest?

The progestin component, norgestimate, has two primary roles described in the mechanism of action. It works to increase the viscosity and thickness of the cervical mucus to physically impede sperm from reaching the egg. It also induces changes in the lining of the uterus (endometrium).

Q: Why do some people experience nausea when they first start Cilest?

Nausea is listed as a Common side effect that is often attributed to the body adjusting to the hormone components, particularly the estrogen. It is typically noted to resolve over the initial cycles of use.

Q: Does Cilest have an impact on weight according to regulatory data?

Yes, regulatory documents list weight change as an officially classified Common adverse reaction. This is provided as part of the known safety profile derived from clinical study reports.

Q: What do official leaflets say about the possibility of skin changes (acne) while taking Cilest?

Official information describes the progestin component, norgestimate, as a third-generation progestin that is characterized as having minimal intrinsic androgenic activity. The classification as minimal intrinsic androgenic activity is a factor relevant to skin outcomes.

Q: Is there any data concerning Cilest and changes in sexual desire?

Yes, changes in sexual desire (specifically libido changes) are listed as a possible adverse reaction in official regulatory documents. This is part of the established safety and side effect profile.

Q: Is Cilest described as a reversible form of contraception?

Cilest is officially described and indicated in regulatory documents as a reversible means of birth control (systemic contraception) for females of reproductive potential. This indicates that it is designed to prevent pregnancy only while it is being used.

Q: What kind of studies led to the approval of Cilest?

Regulatory approval for Cilest was based on large-scale Randomized Controlled Trials (RCTs) and long-term observational studies designed to measure pregnancy rates (Pearl Index) in the study populations.

Q: What happens if I vomit or have severe diarrhea shortly after taking Cilest?

Official guidance warns that vomiting or severe diarrhea may prevent the complete absorption of the active hormones, which could affect effectiveness. Official guidance often specifies a time-frame (e.g., 2 hours) after which hormone absorption may be affected, requiring discussion about maintaining protection.

Q: Can grapefruit or grapefruit juice interact with Cilest?

The interaction section in the official product information explicitly documents that Grapefruit juice may increase the plasma concentrations of the hormone components of the medication. This is due to its documented effect on certain metabolic enzymes.

Q: Can the effectiveness of Cilest be compromised by certain anti-seizure medications?

Yes, certain anti-seizure medications, often referred to as anticonvulsants, are documented in regulatory sources as strong enzyme inducers. These inducers can significantly decrease the exposure to the contraceptive hormones, risking a reduction in effectiveness.

Q: Can non-prescription medicines interfere with Cilest?

Products containing the herbal supplement St. John’s wort are officially restricted from use with Cilest due to documented risks of reduced effectiveness. Additionally, some other non-prescription drugs may affect the hormones' metabolism, risking reduced protection.

Q: Can Cilest affect the results of any common lab tests?

Official regulatory documents indicate that Combined Oral Contraceptives are documented to influence the results of certain laboratory tests. These can include tests for liver function, thyroid-binding globulin, and coagulation factors.

Q: What type of monitoring is described in official guidelines for people using Cilest?

Official guidelines recommend regular blood pressure monitoring and periodic medical evaluation during use. This is primarily done to monitor for the potential development of certain risk factors, such as those related to serious vascular events.

Q: Are there age limits described in the regulatory information for taking Cilest?

Use is absolutely contraindicated (must not be used) for women over 35 years of age who smoke. The medicine is also not indicated for use in geriatric or postmenopausal women, as its safety and efficacy have not been established in those populations.

Q: Does Cilest contain lactose or other inactive ingredients that might cause issues?

The tablets are documented in the official excipients list to contain lactose monohydrate as an inactive ingredient. This fact is relevant for individuals with lactose intolerance or sensitivity.

Q: How is Cilest typically packaged or dispensed?

Cilest is a 21-day pill regimen, typically dispensed in a blister pack containing 21 active hormone tablets to be taken daily. This is followed by a 7-day pill-free interval before the next active pack is started.

Q: What is the official purpose of the inactive tablets in a Cilest pack?

Inactive (non-hormonal) tablets, if present in the pack, are included to support maintaining a daily routine and cycle tracking. The inclusion of these tablets supports starting the next active pack on the correct day.

Q: Is Cilest described as a reversible form of contraception?

Cilest is officially described and indicated in regulatory documents as a reversible means of birth control (systemic contraception) for females of reproductive potential. This indicates that it is designed to prevent pregnancy only while it is being used.

How should Cilest be stored and disposed of?

How to Store and Dispose of Cilest?

Cilest (Ethinyl Estradiol/Norgestimate) tablets must be stored according to official regulatory guidelines to maintain their stability.

Storage Requirement Official Condition
Temperature Store at controlled room temperature: 20^circC to 25^circC (68^circF to 77^circF).
Environment Must be protected from light, excess heat, and excess moisture.
Packaging Keep the medication in its original container and ensure the container is tightly closed.
Child Safety Keep the product out of the sight and reach of children, storing it in a safe, up and away location.

Storage rules strictly prohibit keeping the medication in high-humidity areas, such as the bathroom. Unneeded or expired tablets must be disposed of safely. Official instructions require that disposal prevents access by children or pets and should follow community drug take-back or disposal programs.

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

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