Topasel

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Topasel

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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 Topasel

Quick Facts

Property Description
Active Ingredients Algestone Acetophenide (Progestogen), Estradiol (Estrogen)
Form Solution for injection (Oil solution)
Pharmacological Class Sex-hormonal preparation, Combined injectable contraceptive (CIC)
Common Use Prevention of pregnancy
Origin Synthetic steroid derivatives

Topasel: Definition, Type, and Identity

Topasel is a prescription-only medication classified as a first-generation combined injectable contraceptive (CIC), which places it within the general pharmacological class of sex-hormonal preparations. The product is defined by its convenience as a monthly injection, distinguishing it significantly from oral contraceptive forms that require daily adherence. Combined injectable contraceptives containing an estrogen component, such as Topasel, generally result in more regular bleeding patterns compared to progestin-only injectable methods, which often enhances patient acceptability. This medicine is exclusively a sterile solution for injection administered via the intramuscular route.

Composition, Origin, and Purpose

Topasel is a combination product that delivers two synthetic steroid derivatives: the potent progestogen Algestone Acetophenide (DHPA) and the estrogen Estradiol, typically supplied as the long-acting ester, Estradiol Enantate (E2-EN). This specific combination is unique for its prolonged depot effect achieved through its oil solution vehicle, administered into the muscle tissue. The primary therapeutic purpose of this dual-component system is the effective, systemic prevention of pregnancy in women. The formulation's status as a first-generation CIC, in use since the 1960s, is supported by considerable clinical experience regarding its efficacy in its general use scenario.

Regulatory References

  1. WHO Family Planning Guidance: Monthly Injectables

What side effects are possible with Topasel?

Adverse Reaction Scope

The official safety profile of Topasel (Algestone Acetophenide/Estradiol Enantate) is defined by a range of hormonal adverse events and serious risks associated with the combined injectable contraceptive (CIC) class.

Classification Effects / Systems
Common / Most Frequent Bleeding disorders (e.g., irregular bleeding, spotting), headache, mastalgia (breast tenderness), and weight gain are frequently documented, particularly in the initial cycles of use.
System-Organ Classes Effects are distributed across Reproductive System and Breast Disorders, Nervous System Disorders, Psychiatric Disorders, and Metabolism and Nutrition Disorders.
Serious Adverse Reactions Regulatory information highlights the potential for thromboembolic events (blood clots), including deep vein thrombosis, pulmonary embolism, stroke, and myocardial infarction, as a class risk for combined hormonal products. The risk of benign or malignant liver tumors is also documented.

Safety Classifications (High-Level)

Dose- or Exposure-Related Patterns: The incidence of the most common adverse events, such as irregular bleeding, is documented to be highest at the beginning of treatment and often observed to decrease spontaneously after the initial months of use. Conversely, the risks for serious vascular events are officially documented to be increased by factors such as smoking and age over 35 years.

Safety-Related Restrictions: Use is restricted in patients with a history of or current thromboembolic disorders and in cases of severe hepatic impairment or liver disease, reflecting the high-level safety limitations for combined hormonal therapy.

Connection to the overall safety profile

The regulatory safety structure separates high-frequency, transient hormonal effects from the low-frequency, severe vascular and hepatic risks associated with the entire drug class. This distinction, along with safety limitations based on patient risk factors, ensures that both common expected effects and critical systemic risks are communicated according to governmental mandates.

Overdose and Emergency Response

The official regulatory documentation classifies the acute presentation of a Topasel overdose (Algestone Acetophenide/Estradiol) by specific clinical manifestations. Overdose symptoms are typically documented as not serious or life-threatening.

Classification Official Regulatory Statement
Documented Manifestations Nausea, Vomiting, and Withdrawal Bleeding (vaginal hemorrhage) are recognized clinical signs.
Management Basis No specific antidote is known; management is limited to symptomatic treatment and supportive measures.
Severity Note Acute overdose is generally classified as typically not serious.

Required Emergency Actions

When an overdose is suspected, official labeling mandates specific, immediate actions. The user is required to seek immediate medical attention for assessment. While acute symptoms are generally non-severe, the user must contact emergency services immediately if severe, concerning, or life-threatening clinical signs are observed.

Regulatory information also notes a specific population consideration: Vaginal bleeding is a documented manifestation that may occur in pre-menarche females following accidental exposure to the medicine, which warrants medical assessment. Hospital monitoring and clinical observation may be required based on the severity and persistence of the manifestations. All management procedures must follow the supportive measures described in authorized prescribing information.

Therapeutic Uses of Topasel

What Topasel Treats: Main Uses and Benefits

The medication helps address symptom clusters related to systemic imbalance and is used in situations involving certain distressing symptoms. This category of treatment can offer symptomatic relief relevant for managing symptoms that interfere with daily comfort. It is considered relevant in conditions characterized by periods of heightened symptoms, such as those involved in episodic or fluctuating manifestations.

“It provides support that helps ease the overall symptom burden and assists with maintaining functional stability.”

The medication is applied across domains where additional symptomatic support is commonly needed. The areas of use include supportive management of reproductive cycle symptoms, assistance in symptom-driven control, and easing distressing manifestations in hormonal domains.

The medication is applied in clinical settings that involve acute or unstable symptom patterns. It is relevant for easing symptoms that create noticeable physiological strain and provides supportive relief when symptoms interfere with routine activities. This contributes to improved day-to-day comfort during periods of heightened symptoms.


Quick Fact: Relief for Systemic Imbalance The medication helps patients cope more steadily with symptom fluctuations and supports general well-being during symptomatic phases.

Eligibility and Restrictions for Use

Eligibility Profile: Who Can and Cannot Use Topasel?

This section outlines the specific populations, conditions, and physiological states where the use of Topasel is officially restricted or prohibited, as defined by governmental regulatory documents. The medicine is strictly contraindicated (prohibited) for use in individuals who meet any of the following criteria.

Populations That Must Not Use Topasel (Contraindications):

The following clinical or physiological states represent absolute exclusions for using this medicine:

  • Vascular/Thromboembolic History: Patients with a history of thrombophlebitis or other thromboembolic disorders, as well as those with coronary arterial insufficiency, cerebral arterial insufficiency, or who have had a myocardial infarction (heart attack).
  • Liver Function and Tumors: Individuals diagnosed with advanced hepatic insufficiency or those with known liver tumors.
  • Hormone-Dependent Neoplasia: Patients with breast carcinoma or any other officially diagnosed estrogen-dependent neoplastic processes.
  • Pregnancy Status: Use is strictly prohibited for women with a known or suspected pregnancy.
  • Undiagnosed Bleeding: Patients experiencing undiagnosed vaginal hemorrhages (vaginal bleeding without a determined cause).

Eligibility-Related Restrictions:

The medicine is not established for use in all populations. Use in specific groups, such as children, or in patients with less severe forms of certain conditions, is not covered by these contraindication rules, but must be considered in the overall clinical context. The formal classification of Contraindicated means the risk in these listed situations is considered unacceptable by regulatory bodies.

What should I know about interactions with other medicines?

Interactions with other medicines and products

Topasel's officially documented interaction profile is primarily structured around substances that affect the clearance of its two synthetic steroid components (Algestone Acetophenide and Estradiol).

Formal Contraindications

Co-administration is strictly prohibited with specific Hepatitis C Virus (HCV) antiviral regimens. This restriction applies to combinations containing agents such as ombitasvir/paritaprevir/ritonavir, dasabuvir, glecaprevir/pibrentasvir, and sofosbuvir/velpatasvir/voxilaprevir. This prohibition is due to the documented risk of significant liver enzyme elevation and hepatotoxicity.


Pharmacokinetic Interactions

The most common interactions involve changes in hormone systemic exposure (AUC/Cmax) mediated by hepatic enzymes, principally CYP3A4.

Interaction Type Substance Category Official Outcome
Exposure Decrease CYP3A4 Enzyme Inducers (e.g., certain antiseizure medications, antimycobacterials, St. John's wort) Reduced hormone levels and increased clearance, officially associated with potential loss of effectiveness.
Exposure Increase CYP3A4 Enzyme Inhibitors (e.g., certain protease inhibitors, macrolides) Increased systemic exposure of the hormone components.

Other Documented Effects

A documented pharmacodynamic interaction exists where co-administration with Topasel causes a reduction in the plasma concentration of Lamotrigine due to enhanced glucuronidation. No mandatory timing separation rules are officially documented for interaction management.

Mechanism of Action

The mechanism of action for Topasel relies on the combined, synergistic actions of its two active steroid components, Algestone Acetophenide and Estradiol, to modulate reproductive physiological processes.

The primary action involves the agonism of Progesterone ( PR) and Estrogen ( ER) receptors in the central nervous system, triggering a strong negative feedback loop on the Hypothalamic-Pituitary-Ovarian (HPO) axis . This molecular action suppresses the secretion of the pituitary hormones Luteinizing Hormone ( LH) and Follicle-Stimulating Hormone ( FSH), thereby inhibiting the maturation of the dominant follicle and eliminating the cyclical LH surge. The resulting physiological consequence is the inhibition of ovulation (anovulation).

In parallel, the progestogen component modulates local processes by increasing the viscosity and density of the cervical mucus, creating a physical barrier that impedes sperm transport. Simultaneously, the hormones alter the lining of the uterus, leading to endometrial unreceptivity. The Estradiol component acts synergistically to enhance the central suppression of FSH, leading to sustained inhibition of follicular development.

Dosage and Administration Information

Topasel is a combined injectable contraceptive consisting of two active ingredients, estradiol enantate and algestone acetophenide (also known as dihydroxyprogesterone acetophenide or DHPA). It is administered as an intramuscular injection into the muscle tissue.

Dosage and Administration

Topasel is typically administered once a month on a fixed schedule. The common formulation contains 10 mg of estradiol enantate and 150 mg of algestone acetophenide.

  • Method: The injection must be given deep into the muscle (intramuscularly) by a qualified healthcare professional. This route of administration ensures the hormones are absorbed slowly over time to provide a long-lasting contraceptive effect, often extending for 20 to 30 days.
  • Frequency: The medication is administered on a monthly basis, usually 30 days (plus or minus 3 days) apart. Adherence to the prescribed schedule is critical for ensuring effectiveness.
  • Initial Dose: The first injection is typically given during the first five days of the menstrual cycle, though specific timing may be adjusted by a healthcare provider based on individual circumstances.

Important Considerations

Patients should use the lowest effective dose for the shortest duration consistent with their treatment goals. Before and during the use of any injectable contraceptive, a medical professional must conduct a full medical history and physical examination to ensure the treatment is appropriate and safe.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Topasel

Topasel, a combination of Algestone Acetophenide and Estradiol Enantate, is classified as a first-generation Combined Injectable Contraceptive (CIC). The research record for this product is available across decades, primarily through large international clinical programs and observational reports.


Evidence for Use in Pregnancy Prevention (Contraception)

Studies have primarily examined Topasel's use in the prevention of pregnancy. Research has explored this combination using multicenter prospective clinical trials and extensive observational reports. These studies monitored key outcomes related to systemic or functional imbalance, such as the Pearl Index (a measure of how often pregnancy occurs during use) and monitoring whether the treatment method stops ovulation.

Studies reported measurements of the pregnancy rate (Pearl Index) within the cohorts observed. Research describes patterns where the suppression of ovarian function was monitored for approximately 30 days following the injection.

Comparative evidence is lacking regarding direct, head-to-head Randomized Controlled Trials (RCTs) against all the newer combined injectable contraceptives available today, according to systematic reviews. There is also limited information for long-term outcomes, and high patient discontinuation rates mean data for continuous users in a research setting are less comprehensive.


Research on Menstrual Cycle and Bleeding Patterns

Studies have explored the relationship between Topasel and menstrual cycle characteristics. This research was evaluated in sub-analyses within efficacy trials and in comparative studies contrasting combined injectable methods with progestin-only injectable methods. Researchers examined outcomes related to physical discomfort, such as the frequency and occurrence of spotting, unscheduled bleeding, and painful menstruation (dysmenorrhea).

Findings describe patterns observed in the studies where the estrogen component was evaluated alongside progestin-only injectables for outcomes related to the regularity of withdrawal bleeding. Studies reported how symptoms evolved in the observed populations, documenting measurements related to the average duration of bleeding and the frequency of painful menstruation among users over several cycles of use.


Research Gaps and Limitations

Systematic reviews and regulatory documentation describe areas where the research base for Topasel remains uncertain.

The follow-up durations were limited in many of the key trials, focusing primarily on the first year of use. Comparative evidence is lacking for a comprehensive assessment against all newer hormonal methods. Furthermore, the existing evidence focuses on the primary outcome of contraceptive efficacy and the secondary outcome of cycle control. Long-term effects on other non-contraceptive health outcomes are not well characterized.

Frequently Asked Questions (FAQ)

Common questions about Topasel (FAQ)


Q: How quickly do people usually start to notice Topasel working?

According to official product information, Topasel's contraceptive action is designed to begin immediately if the initial injection is administered within the specified schedule. The medicine works by suppressing ovulation shortly after it is correctly administered. Maintaining effectiveness is linked to strict adherence to the planned monthly injection date.


Q: Can Topasel be used for conditions other than its primary approved use?

Topasel is officially designated for one specific therapeutic purpose: the effective, systemic prevention of pregnancy. Regulatory documents only provide evidence and recommendations for this approved indication. Any discussion or recommendation regarding other uses is not contained within the official product labeling.


Q: Is it normal to feel slightly dizzy when first starting Topasel?

Dizziness is a documented neurological side effect associated with the hormonal components, such as estradiol, found in Topasel. While it may not be listed among the most common adverse reactions, product labels note that it is a possible effect. Persistent or severe symptoms are reasons for professional consultation.


Q: Are there any common foods or drinks that should be avoided while taking Topasel?

Official guidance on hormonal contraceptives often advises caution regarding the consumption of grapefruit and grapefruit juice. Grapefruit is known to affect the body's metabolism of certain estrogens. Individuals are advised to seek descriptive information from a medical professional on potential dietary interactions.


Q: What happens if I forget to take a dose of Topasel?

Official information states that adherence to the once-a-month schedule (30 pm 3 days) is critical for effectiveness. Missing the scheduled date is associated with a factual loss of contraceptive protection. Because the medicine is administered by a healthcare professional, they can explain the factual consequences of any delay.


Q: Is Topasel safe to use if I have kidney problems?

Hormonal contraceptives are known to influence fluid retention in the body, which may affect people with pre-existing kidney issues. Regulatory information notes that individuals with known kidney dysfunction typically require professional review before starting this therapy. This helps ensure the treatment is appropriate.


Q: Can Topasel affect the results of certain lab tests?

Yes, combined hormonal contraceptives may influence the results of various laboratory tests, according to official warnings. This can include parameters related to liver, thyroid, adrenal, and renal function. Disclosure that Topasel is being used is a standard requirement before certain lab work is ordered.


Q: What is the risk of having an allergic reaction to Topasel?

Rare cases of severe allergic reactions (hypersensitivity or anaphylaxis) have been reported for the hormonal components used in Topasel. Official documentation states that signs of a severe reaction, such as swelling or difficulty breathing, are important and require immediate attention.


Q: Can Topasel make me feel tired or lethargic?

Tiredness or fatigue is a known systemic effect that can be associated with hormonal birth control. While it may not be highlighted as one of the most common adverse reactions, it is documented in the broader side effect profile. Persistent or severe symptoms are reasons for professional consultation.


Q: Can I drive or operate machinery while taking Topasel?

Official information generally states that Topasel is not expected to impair the ability to drive or use machinery. This is based on the assumption that the user does not experience specific side effects that affect attention. Users experiencing side effects like dizziness or severe headaches are advised by regulatory bodies to exercise caution.


Q: Does Topasel interact with alcohol?

Acute ingestion of alcohol can factually increase the circulating levels of estradiol in the bloodstream. Due to this potential interaction, regulatory guidance often suggests limiting alcohol intake when using estrogen-containing products.


Q: Is Topasel considered a controlled substance?

No, Topasel is a sex-hormonal preparation classified as a combined injectable contraceptive. It is not listed as a controlled substance in the US or most international drug control schedules. It is, however, a prescription-only medicine.


Q: What happens when Topasel leaves the body?

The hormonal components of Topasel are primarily metabolized in the liver after their contraceptive function is complete. The main component, Algestone Acetophenide, is mostly eliminated through the feces. Metabolites of the drug can be detectable in the body for up to two months following the injection.


Q: Are there any specific activities to avoid while on Topasel?

The most significant specific warning in official documentation relates to smoking. Smoking significantly increases the risk of serious vascular events (blood clots) associated with combined hormonal contraceptives. The regulatory information describes smoking as a strictly avoided factor, particularly for women over 35 years of age.


Q: Is it possible to overdose on Topasel?

Official product information contains data on potential overdose symptoms related to the estrogen component. These symptoms may include nausea, vomiting, breast tenderness, drowsiness, and fatigue. The official management strategy includes discontinuation of the medicine and symptomatic care.


Q: What happens if Topasel is taken with grapefruit?

Grapefruit and its juice are known to inhibit the enzyme responsible for breaking down the estradiol component of Topasel. This effect could lead to increased hormone levels circulating in the body. Higher hormone levels may be associated with an increase in estrogen-related side effects, such as headaches or nausea.


Q: Is Topasel safe for people who are lactose intolerant?

Topasel is formulated as a sterile solution for injection in an oil vehicle. Since it is not a solid oral dosage form, the official list of excipients confirms that it does not contain lactose. This means it is an option for individuals with lactose intolerance, as it does not contain the ingredient.


Q: What is the difference between Topasel and [similar drug X]?

Topasel is defined as a specific combination of Algestone Acetophenide and Estradiol Enantate. Its difference from other combined contraceptives lies in its specific hormonal components, strength, and its route of administration as a monthly intramuscular injection. Other contraceptives may differ in chemical makeup, dosage strength, or frequency of use.


Q: Can older adults or the elderly safely use Topasel?

Official warnings state that the risk of serious vascular events, such as blood clots, is factually increased in women who are older, especially those over 35 years of age. Topasel's approved use is primarily for women of reproductive age. Regulatory documents require that individual risk factors be professionally assessed.


Q: What are the most common reasons someone would stop taking Topasel?

Clinical study data indicates that the most common reasons for discontinuation are related to frequent, non-serious side effects. These include changes in menstrual bleeding patterns (such as irregular bleeding or spotting), headache, and weight gain. These effects are most often reported during the initial cycles of use.


Q: Has Topasel been studied in children or teenagers?

Official information states that Topasel is generally not recommended for use before menarche, which is the start of menstruation. There are limitations in specific studies documenting safety and efficacy exclusively in children. Its use is focused on the reproductive years.


Q: What is the purpose of the different strengths (mg) of Topasel?)

Different strength formulations of Topasel exist in various markets. The specific combination of milligrams of Estradiol Enantate and Algestone Acetophenide is chosen for the purpose of contraception. This is intended to allow for the use of the lowest effective dose necessary for pregnancy prevention.


Q: How long do patients typically take Topasel for?

Topasel is administered continuously, once a month, for as long as contraception is required. Official guidance recommends using the product for the shortest duration that is consistent with the patient's treatment goals. There is no predetermined maximum duration specified in the official documents.


Q: Can Topasel be used during pregnancy or while breastfeeding?

Official documents strictly prohibit the use of Topasel during a known or suspected pregnancy. Regulatory guidance also advises against its use during breastfeeding. The restriction is based on the possibility that hormonal components could be excreted in breast milk and potentially reduce milk production.


Q: Are the side effects of Topasel permanent or do they go away?

Common hormonal side effects, such as irregular bleeding, are often transient and tend to decrease spontaneously after the initial months of use. However, serious, low-frequency risks, such as blood clots or liver tumors, are defined as critical systemic risks. Professional review of all risks, particularly the serious ones, is required by regulatory documents.


Q: Can I take Topasel if I already take another daily medicine?

Yes, Topasel has documented interactions with several classes of drugs, including certain antivirals and enzyme inducers or inhibitors. The interactions profile indicates that all other medications should be reviewed with a healthcare provider prior to starting Topasel. The purpose of this review is to facilitate consideration of all potential impacts.


Q: Why might Topasel be less effective for some people than others?

Effectiveness can be reduced by factors that increase the body's rate of hormone clearance. This includes taking certain medicines, such as antiseizure drugs, that induce liver enzymes. Additionally, missing the monthly injection appointment can also lead to a loss of contraceptive effectiveness.

How should Topasel be stored and disposed of?

How to Store and Dispose of Topasel?

Official regulatory documents define strict storage and disposal requirements for the Topasel (Estradiol Enantate/Algestone Acetophenide) injectable solution.


Storage Requirements

Condition Regulatory Rule
Temperature Store below 30, C. Do not refrigerate or freeze.
Protection Keep in the original outer carton to protect from light.
Safety Keep out of the sight and reach of children.

Disposal Requirements

Topasel is a single-use injectable and must be disposed of correctly.

Used needles and syringes (sharps) must be placed immediately into an approved, puncture-proof sharps disposal container.

All unused product and waste material must be disposed of in accordance with local pharmaceutical waste regulations. Medicines must not be disposed of via household waste or wastewater to prevent environmental contamination by the hormonal components.

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

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