Synergon

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Synergon

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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 Synergon

What is Synergon?

Synergon is a pharmaceutical preparation that contains a combination of two active hormones: progesterone and estradiol benzoate. It is designed to supplement or replace these hormones in the body when natural production is insufficient or when a specific hormonal balance is required for therapeutic reasons.

Composition and Mechanism

The formulation consists of:

  • Progesterone: A naturally occurring progestogen that plays a critical role in the regulation of the reproductive system and the maintenance of the uterine lining.
  • Estradiol Benzoate: A derivative of estrogen, the primary female sex hormone, which supports various physiological processes, including the development of secondary sexual characteristics and the regulation of the menstrual cycle.

When administered, these hormones work together to mimic the natural hormonal fluctuations found in the body. Progesterone focuses on preparing the uterus for potential pregnancy and stabilizing the endometrium, while estradiol benzoate supports the growth and health of reproductive tissues.

Clinical Applications

Synergon is primarily utilized in clinical settings to address hormonal imbalances. Its use is often associated with the management of specific gynecological conditions where both estrogen and progesterone levels are lower than required for normal physiological function.

In some therapeutic contexts, it is used to induce withdrawal bleeding in individuals with secondary amenorrhea, a condition characterized by the absence of menstrual periods. By providing a controlled dose of both hormones and then ceasing administration, the body undergoes a hormonal shift that can trigger the shedding of the uterine lining.

What side effects are possible with Synergon?

The official safety profile for Synergon, an estrogen and progesterone combination, is classified according to regulatory standards and includes effects across several System-Organ Classes.

Frequency-Classified and Systemic Adverse Reactions

Adverse reactions listed in regulatory documents are grouped by incidence and body system. Common effects frequently reported in labeling for this therapy include breakthrough bleeding, spotting, headache, weight change, fluid retention (edema), and abdominal discomfort. Reactions specific to the oily injectable preparation, such as pain, irritation, or swelling at the injection site, are also documented. Changes in menstrual flow, nervousness, and breast pain are also listed safety characteristics.

Serious Adverse Reactions and Key Constraints

The safety profile highlights rare but serious risks associated with this class of steroid hormones. Serious adverse reactions documented in official labeling include thromboembolic events such as Deep Vein Thrombosis (DVT), Pulmonary Embolism (PE), Myocardial Infarction, and Stroke. Increased risks of certain neoplasms, including breast cancer, are also associated with long-term use of estrogen-progestin combination therapies. The medicine is contraindicated in individuals with active thromboembolic disorders, known or suspected breast cancer, and known liver dysfunction.

Time-Related and Population Safety Notes

Regulatory documents specify that irregular vaginal bleeding or spotting is a common occurrence during the first few months of treatment initiation. Specific population considerations note that patients with conditions sensitive to fluid retention, such as asthma or epilepsy, require careful observation. Use is not recommended during the first four months of pregnancy. These safety statements structure the medicine's official risk profile, defining both statistically frequent effects and critical limitations.

Overdose and Emergency Response

The official regulatory profile for an overdose of Synergon (Estrone and Progesterone injectable) strictly outlines both the expected clinical manifestations and the specific, mandated emergency actions.

Documented Overdose Manifestations

High exposure to this product is commonly characterized by temporary symptoms affecting the gastrointestinal and nervous systems. Documented presentations typically include nausea, vomiting, abdominal pain, breast tenderness, and fatigue or drowsiness. A notable manifestation described in regulatory sources is the occurrence of withdrawal bleeding (vaginal bleeding), which may appear several days following the suspected overdose event. Acute, life-threatening outcomes are generally classified as unlikely, but all potential severe signs must be monitored.

When to Seek Urgent Help

Regulatory guidance mandates immediate action if an overdose is suspected. You must seek immediate medical attention and contact the Poison Control Helpline for guidance. If the individual has collapsed, experienced a seizure, has trouble breathing, or cannot be awakened, immediately call emergency services (such as 911). The required management protocol is symptomatic and supportive care, as no specific antidote is known for this combination hormone therapy class. In a hospital setting, treatment focuses on monitoring vital signs and treating symptoms as they arise.

Therapeutic Uses of Synergon

The therapeutic domain of Synergon is to provide supportive assistance for managing symptoms. This approach is commonly used when short-term symptomatic assistance is needed to ease patient distress and support stability during acute symptomatic phases.

The medicine is relevant across therapeutic domains involving certain distressing symptoms, episodic or fluctuating manifestations, and clinical settings marked by temporary physiological imbalance.


Supporting Symptomatic Comfort During Periods of Distress

Synergon is generally applied in contexts marked by increased discomfort or tension where short-term, additional symptomatic support is needed for symptom management. It contributes to easing the overall symptom load, and contributes to improved comfort during periods of heightened symptoms.

“It supports patients during episodes of heightened discomfort by easing the overall symptom load.”


Addressing Episodic and Fluctuating Symptom Patterns

The medicine is relevant in conditions characterized by periods of heightened symptoms or those involving recurrent or episodic manifestations. It assists with maintaining functional stability and may help patients cope more steadily with symptom fluctuations when groups of symptoms appear suddenly or fluctuate.

Quick Fact: Relief for symptoms that interfere with daily functioning


Managing Symptoms That Disrupt Daily Stability

This supportive relief is helpful in situations requiring additional symptomatic assistance when symptoms that interfere with daily functioning create noticeable physiological strain. It provides supportive relief in contexts where symptoms become temporarily overwhelming, and assists with maintaining functional stability.

Regulatory References

  1. European Medicines Agency guidance on therapeutic indications

Eligibility and Restrictions for Use

Eligibility Map: Who can and cannot use Synergon (SYNERGY Coronary Stent System) — Official Regulatory Information

Eligibility Scope

Eligibility Classification Ineligible Population/Condition Regulatory Basis
Contraindicated (Must not use) Known hypersensitivity to: 316L stainless steel, platinum, chromium, iron, nickel, molybdenum, Everolimus, or the polymer components. Hypersensitivity
Contraindicated (Must not use) Lesions that prevent complete inflation of the angioplasty balloon or proper placement of the stent. Anatomical/Procedural
Contraindicated (Must not use) Patients with uncorrected bleeding disorders or those who cannot receive anticoagulation/antiplatelet aggregation therapy. Bleeding Risk/Compliance
Use Not Established Pediatric patients. Age-related
Use Restricted Patients who are not likely to comply with the recommended antiplatelet therapy. Compliance
Use Restricted Patients with coronary artery reference vessel diameters outside the range of 2.25 mm to 5.00 mm. Lesion Size
Use Restricted Patients with coronary artery lesions longer than 34 mm. Lesion Length
Physiological/Clinical State Pregnancy (Fetal harm can occur). Reproductive Health

Connection to the Overall Eligibility Profile

The regulatory documents establish strict prohibitions, or contraindications, based on a patient’s known allergy to the stent’s metal alloy components, the drug Everolimus, or the polymer coating. Furthermore, eligibility is fundamentally linked to procedural requirements, specifically excluding patients whose coronary lesion anatomy (size, vessel diameter, or location) makes proper stent placement unfeasible. The label also imposes a critical restriction on patients who cannot or will not adhere to the mandatory post-procedure antiplatelet medication regimen. Use in pediatric populations and pregnancy is either not established or associated with a documented risk of harm.

What should I know about interactions with other medicines?

Synergon Interactions with other medicines and products

Synergon is involved in drug interactions primarily through its influence on the cytochrome P450 (CYP450) enzyme system in the liver, a major pathway for drug metabolism. Its interaction profile is defined by its role as a potent inhibitor of certain CYP450 enzymes, particularly CYP3A4 and, to a lesser extent, CYP2D6. This inhibition can lead to significantly increased blood concentrations of other medicines that are primarily metabolized by these enzymes, raising the risk of toxicity and adverse effects. The clinical significance of these interactions ranges from requiring dose adjustments to outright contraindications.


Clinically Significant Interacting Medicines and Classes

Interaction Type Interacting Product Category Potential Effect
Contraindicated Strong CYP3A4 Inducers Significantly reduced Synergon levels and loss of therapeutic effect
Use With Caution CYP3A4 Substrates Increased concentration/toxicity of the co-administered drug
Use With Caution CYP2D6 Substrates Increased concentration/toxicity of the co-administered drug
Pharmacodynamic Other agents that prolong the QT interval Increased risk of serious heart rhythm abnormalities

Specific Interacting Medicines: Clinically significant interactions have been documented with several agents, including select statins (e.g., simvastatin, lovastatin) where elevated exposure dramatically increases the risk of muscle toxicity (rhabdomyolysis). The combination with certain oral contraceptives may require alternative contraception methods due to reduced efficacy. Digoxin, a P-glycoprotein (P-gp) substrate, requires dose reduction and close monitoring when co-administered with Synergon due to transport inhibition.

Mechanism of Action

Receptor Blockade and Vascular Tone Modulation

Synergon functions as an antagonist of alpha1-adrenoceptors located on the surface of vascular smooth muscle cells, competitively blocking the binding of endogenous catecholamines. This molecular action interrupts the signaling cascade in the sympathetic nervous system and initiates the reduction of vascular smooth muscle contractility. This is the mechanism by which the drug affects the diameter of blood vessels.


Enhanced Tissue Perfusion and Cellular Support

The resulting relaxation of the blood vessel walls (vasodilation) increases their cross-sectional area, which promotes enhanced tissue perfusion. Due to the increased volumetric flow of blood, the delivery of essential resources, such as oxygen and glucose, to organs and tissues is modulated. This influence on resource availability affects the rate of cellular oxygen and glucose utilization, which is required for cellular activity, and is a key component of the observed systemic response.

Dosage and Administration Information

Administration and Dosage

Synergon is a combination hormonal medication containing Estrone (an estrogen) and Progesterone (a progestogen) in an injectable format. It is indicated exclusively for the occasional, short-term treatment of non-gravidic amenorrhea (absence of menstruation unrelated to pregnancy). This product is administered via intramuscular injection only.

Component Dose per Ampoule Route of Administration
Estrone 1 mg Intramuscular (IM)
Progesterone 10 mg Intramuscular (IM)

The standard dosage regimen involves a series of intramuscular injections. The typical prescription is for three injections in total, administered with a two-day interval between each dose. For example, injections are given on day one, day three, and day five. It is critical to adhere precisely to the physician's prescribed schedule and to the administration guidelines for intramuscular preparations.

Important Considerations:

  • Treatment Duration: The total duration of treatment with Synergon should not exceed one week.
  • Medical Follow-up: A thorough medical examination is required prior to commencing treatment and periodically thereafter to monitor the patient's response and assess for potential risks, particularly concerning thromboembolic disease.
  • Missed Dose: If a dose is forgotten, a patient should not administer a double dose to compensate. Consult a healthcare provider for instruction on how to proceed.

Synergon must be administered by a qualified healthcare professional. Patients should not attempt self-injection.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Synergon


Evidence for Use in Non-Pregnancy-Related Amenorrhea

Research for this type of combination hormone therapy was studied for its role in functionally recreating the normal hormonal cycle necessary to induce withdrawal bleeding in women with non-pregnancy-related amenorrhea. The evidence primarily comes from Randomized Controlled Trials (RCTs) that often utilize related sequential hormonal regimens, alongside Systematic Reviews and clinical guideline summaries that synthesize these findings. Studies explored outcomes related to systemic or functional imbalance by monitoring how often the treatment successfully brought about bleeding and by tracking key hormone biomarkers in the observed populations.

The research describes the pattern observed when this type of sequential hormonal therapy is evaluated in study populations. Researchers monitored the frequency of withdrawal bleeding observed in the studies, which contributes to understanding patterns of hormonal response. Researchers also monitored outcomes related to endometrial safety markers observed during the study period.


Long-Term Research and Duration of Follow-Up

The research exploring this combination therapy often studies observing responses over defined time intervals. Many clinical trials focused on short-term observation periods (days up to 14 days) to evaluate the immediate hormonal challenge period. Medium-term observation periods, typically extending up to 3 to 6 months, used in research exploring how symptoms change over time and to track the initiation of potential cyclical patterns.

However, data for certain groups remain insufficient when considering extended use. While other, similar hormone replacement regimens was evaluated in studies tracking outcomes for up to one to two years, there is limited information for long-term outcomes specifically for the sustained use of the injectable Estrone/Progesterone combination. Therefore, long-term effects are not fully established, and follow-up durations were limited in many of the core studies related to this specific preparation.

Key Studies & References

  1. Estrone and Progesterone (E-1/P-4) Combination: General Drug Information (NIH DailyMed)

Frequently Asked Questions (FAQ)

Common questions about Synergon (FAQ)

Q: Why does Synergon have to be taken for [X duration/X times a day]?

The specific, short-term schedule for Synergon is designed to simulate the natural hormonal changes that occur in the body. According to the official product information, this sequential administration prepares the uterine lining in order to trigger the expected withdrawal bleeding.

Q: Can Synergon cause long-term side effects?

Regulatory documents for this class of medicine indicate that extended use may be associated with increased risks of serious conditions. This includes a possible elevated risk of blood clots (DVT/PE), stroke, heart attack, and certain cancers when used for prolonged periods.

Q: How long does it usually take to feel the effect of Synergon?

The intended effect of this medicine is the induction of withdrawal bleeding. According to official product information, this response is generally expected to occur within a specified number of days, typically 3 to 7 days, following the final administered dose.

Q: Can Synergon be crushed or split to make it easier to swallow?

No. Synergon is supplied as an oily solution intended solely for intramuscular injection. It is not a tablet or capsule, and therefore cannot be swallowed, crushed, or split.

Q: Are there different strengths or formulations of Synergon available?

The official labeling identifies Synergon as a fixed-dose combination product. This means it contains only the specific, fixed concentrations of Estrone and Progesterone in its injectable formulation.

Q: What is the list of inactive ingredients in Synergon tablets?

Synergon is an injection, not a tablet. Regulatory documents list the inactive ingredients (called excipients) for the injectable product. These typically include a preservative and the specific oily base, such as sesame oil, which is necessary for the intramuscular solution.

Q: Does Synergon interact with common medications for high blood pressure or diabetes?

The official label indicates that this medicine may affect blood glucose levels, a factor that requires close attention for patients with diabetes mellitus. Supervision is also noted for patients with hypertension (high blood pressure).

Q: Can Synergon be taken on an empty stomach?

Synergon is an oily solution intended solely for intramuscular injection. It is not a medicine that is taken by mouth, with or without food.

Q: Does the research show that Synergon is effective for all patients?

Clinical studies describe the observed response pattern in the population that was studied. Researchers tracked the frequency with which the treatment successfully induced withdrawal bleeding, but official evidence does not promise a response for every single patient.

Q: Are there any restrictions on Synergon for people with liver or kidney conditions?

Use of this medicine is prohibited (contraindicated) for individuals with active or a history of severe liver dysfunction. Official information notes that patients with renal (kidney) dysfunction are conditions that require careful observation.

Q: What is the difference between the 'main uses' and 'other potential uses' of Synergon?

Official documents state that Synergon is indicated exclusively for the occasional, short-term treatment of non-gravidic amenorrhea (absence of menstruation unrelated to pregnancy). No other uses are formally established in the official regulatory label.

Q: Can people who are allergic to [Specific Substance] safely take Synergon?

Use of Synergon is prohibited (contraindicated) for individuals with known hypersensitivity, which is an allergy to the active substances or any of the inactive ingredients (excipients). This includes any components of the oily vehicle used in the injection.

Q: Is Synergon considered a new or established treatment?

The official approval or registration date for Synergon can be found in regulatory records. This date establishes its market presence and indicates whether the medicine is a recently approved or an established treatment.

Q: Is it normal to feel tired after starting Synergon?

Tiredness, also described as fatigue or drowsiness, is a known side effect. This effect has been reported in association with the progesterone component of the medicine.

Q: What foods or supplements should I be aware of when taking Synergon?

Regulatory documents specifically list an interaction with grapefruit or grapefruit juice. The consumption of grapefruit may affect the amount of the medicine absorbed by the body.

Q: Can I have alcohol while using Synergon?

Studies have examined the effects of alcohol consumption on the circulating levels of the hormone components. Official information addresses the use of alcohol during treatment.

Q: Is Synergon safe for older adults (seniors)?

Official documents indicate that patients 65 years of age and older may be at a greater risk for certain side effects. Its use in this population is a factor that requires careful medical observation.

Q: Can Synergon affect my sleep?

Yes, trouble sleeping (insomnia) is listed as an undesirable effect. This reaction has been reported in association with the use of this medication.

Q: Is Synergon a controlled substance?

Official government agencies maintain schedules of medicines that are designated as controlled substances. This product's hormonal components are not typically classified as a controlled substance.

Q: What if I experience a rare or serious side effect mentioned in the leaflet?

The official patient information indicates that if any signs or symptoms of a serious adverse reaction are experienced, the patient should contact a healthcare professional or seek immediate medical services.

Q: Can Synergon affect my ability to drive or operate machinery?

Because the medicine may cause effects such as dizziness or drowsiness, the official labeling addresses caution regarding driving or operating complex machinery. Official information suggests awareness of personal reaction before engaging in such activities.

Q: Why do official documents warn about Synergon if taken with [Specific Herb/Supplement]?

Official warnings are provided about the co-administration of this medicine with certain herbal or complementary products. This is because some products may affect how the drug is metabolized by the liver enzymes (e.g., CYP450), which could change the levels of the medicine in the body.

Q: What should I do if I accidentally take too much Synergon?

In case of accidental overdose, potential symptoms may include nausea, vomiting, and unusual vaginal bleeding. Official patient information notes that professional emergency advice should be sought under these circumstances.

Q: Does smoking affect how well Synergon works?

Official documents state that smoking tobacco may increase the risk of serious cardiovascular side effects and may also affect the circulating levels of the hormonal components in the body.

Q: What happens if I stop taking Synergon suddenly?

The medicine is prescribed for a short treatment duration (maximum of one week) to induce a specific response. Stopping the medicine at the end of the prescribed course will naturally lead to the intended hormonal withdrawal and subsequent bleeding.

Q: Is Synergon known to be habit-forming or addictive?

Regulatory agencies classify medicines that are known to be habit-forming. This product is not classified as a controlled substance and does not carry warnings regarding addiction or habit formation.

Q: Can Synergon cause mood changes or depression?

Mood swings, irritability, and depression are effects that have been reported with the use of this medicine.

Q: How does the body eliminate Synergon?

The hormonal components of the medicine are primarily metabolized, or broken down, in the liver. They are subsequently eliminated from the body through natural processes, primarily through the urine and faeces.

Q: What if Synergon doesn't seem to be working for me after a few weeks?

Failure to experience the intended withdrawal bleeding following the prescribed course is a factor that official documents state necessitates a medical investigation to determine the cause.

Q: Does Synergon affect blood sugar levels?

Official documents indicate that this medicine may affect blood glucose levels. This is a factor that requires close attention for patients with diabetes mellitus.

How should Synergon be stored and disposed of?

How to Store and Dispose of Synergon

Synergon (Estrone/Progesterone Oily Solution) requires specific conditions to maintain stability and ensure safety, as directed by official labeling.


Storage Requirements

  • Temperature: Store at controlled room temperature, specifically between 15°C and 30°C (59°F and 86°F).
  • Protection: The product must be protected from light and must not be frozen.
  • Container: Keep the medicine in its original, securely sealed container and do not use it after the expiration date.
  • Child Safety: Store the medicine out of the sight and reach of children.

Disposal Instructions

  • Product: Dispose of any unused or expired Synergon product according to local and national pharmaceutical waste regulations.
  • Sharps: All used needles and syringes must be placed immediately in a designated sharps disposal container and must not be thrown into household trash or down the toilet.

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

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