Quick Facts

• Support for Early Pregnancy: May be used to support the luteal phase, often within the context of assisted reproductive technology (ART).
• Menstrual Cycle Regulation: Acknowledged use in managing the absence of menstruation (amenorrhea) and certain types of irregular uterine bleeding linked to hormonal imbalance.
• Conditions of Progesterone Deficiency: Intended to address conditions where there is insufficient natural progesterone, such as corpus luteum insufficiency.

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What Lentogest Treats: Main Uses and Benefits

Lentogest (hydroxyprogesterone caproate injection) contains a synthetic progestin and is utilized in therapeutic approaches involving the female reproductive system. It is primarily considered for its role in addressing conditions related to insufficient progesterone.

In gynecological practice, this medication is used in the management of primary and secondary amenorrhea (the absence of a menstrual period). It also contributes to the regulation of certain instances of abnormal uterine bleeding that stem from hormonal imbalances. Additionally, Lentogest may be administered to provide support for the luteal phase as part of a treatment protocol, particularly in fertility contexts.

The medication's applications also encompass circumstances of corpus luteum insufficiency, a condition that may affect the maintenance of early pregnancy. It is intended to offer hormonal support in these specific, medically-directed contexts, aligning with recognized therapeutic applications outside of certain withdrawn indications. The ultimate goal of its use is to assist in stabilizing the hormonal environment required for the relevant physiological process.

Eligibility Map: Who Can and Cannot Use Lentogest — Official Regulatory Information

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The eligibility profile for Lentogest (hydroxyprogesterone caproate) is strictly defined by regulatory documents, which establish absolute non-eligibility for several populations.

Populations for whom use is contraindicated:

• Current or history of thrombotic or thromboembolic disorders (venous or arterial).
• Known or suspected hormone-sensitive cancers (e.g., breast cancer) or a history of these conditions.
• Active liver disease, liver tumors, or severe liver dysfunction.
• Undiagnosed abnormal vaginal bleeding unrelated to pregnancy.
• Uncontrolled hypertension.
• Known hypersensitivity to any component of the formulation.

Age-related eligibility rules:

• Pediatric: The medicine is not indicated for children younger than 16 years of age; safety and efficacy are not established in this population.
• Geriatric: Should not be used in elderly women; safety data in this age group are not available.

Condition-specific eligibility rules (Use with Caution):

• Individuals with cardiac or renal dysfunction, epilepsy, asthma, or migraine require careful monitoring due to the potential for fluid retention.
• Prediabetic or diabetic women must have blood glucose closely monitored as progestins may decrease glucose tolerance.

Pregnancy and lactation eligibility status:

• Pregnancy: The medicine is/was indicated in some jurisdictions for specific use in pregnancy (e.g., to reduce the risk of recurrent preterm birth) but is subject to varying international regulatory status.
• Lactation: Use is not recommended while breastfeeding, as progestins are excreted in human milk.

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Connection to the overall eligibility profile

Regulatory documents define who can and cannot use the medicine by establishing clear contraindications that exclude populations with severe cardiovascular, hepatic, or oncologic risks. The labels also mandate cautious use for populations with certain metabolic or fluid-balance sensitive conditions, and formally exclude the pediatric and geriatric populations where safety data are lacking.

Interactions with other medicines and products

Lentogest (progesterone) interacts with other substances primarily by affecting its metabolism in the liver. These interactions are documented in regulatory labeling and should be considered when co-administering medications.

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Pharmacokinetic Interactions

Lentogest is metabolized by the CYP3A4 enzyme system. This results in significant interactions with drugs that affect this system:

Substance Type	Examples	Effect on Progesterone Exposure
CYP3A4 Inducers	Rifampicin, Carbamazepine, Phenytoin, St. John's Wort	Decreases (potential reduced efficacy)
CYP3A4 Inhibitors	Ketoconazole	Increases (potential increased effect)

Pharmacodynamic and Metabolic Interactions

Co-administration with Lentogest may affect the activity of other medicines:

• Antidiabetic Agents: Progesterone can reduce glucose tolerance or insulin sensitivity. Patients on antidiabetic agents require close observation for potential dosage adjustment.
• Ciclosporin (Cyclosporine): Progesterone may inhibit the metabolism of Ciclosporin, which can lead to increased concentrations of Ciclosporin in the blood.

Condition-Specific Constraints

The use of Lentogest is generally contraindicated in patients with hepatic disease due to the drug's dependence on liver metabolism for clearance, which impacts the predictability and severity of all documented interactions.

Nuclear Receptor-Mediated Signaling Modulation

Lentogest, containing progesterone, functions as a high-affinity agonist for nuclear progesterone receptors (PR). Upon binding, the activated receptor complex translocates into the cell nucleus, where it regulates gene expression by affecting DNA transcription. This process initiates molecular sequences that influence protein synthesis across responsive cellular systems.

Modulation of Myometrial Excitability

The activation of progesterone receptors primarily impacts pathways within the myometrium (uterine muscle). Progesterone signaling suppresses factors that promote uterine smooth muscle excitability, including the downregulation of oxytocin receptor concentrations and the inhibition of prostaglandin synthesis pathways. The net result of this pathway is a reduction in myometrial excitability and a state of low contractility.

Endometrial and Decidual Pathway Modulation

Progesterone is key to maintaining the secretory phase of the endometrium and inducing decidualization. By modulating the expression of specific growth factors, cytokines, and adhesion molecules, this mechanism affects the molecular and cellular composition of the endometrium, which is necessary for the development of the decidua.

Lentogest, containing hydroxyprogesterone caproate (17-OHPC), is an injectable solution typically administered by a healthcare provider. The prescribed regimen depends on the condition being treated, such as reducing the risk of preterm birth or for certain gynecological/fertility disorders.

Administration for Reducing Preterm Birth Risk

For the authorized indication of reducing the risk of recurrent spontaneous preterm birth in women with a singleton pregnancy who have a history of a prior singleton spontaneous preterm birth, the medication is administered as follows:

Administration Detail	Standard Instructions
Dose	Usually 250 mg (1 mL)
Frequency	Once weekly (every 7 days)
Injection Site	Intramuscularly into the upper outer quadrant of the gluteus maximus (buttock)
Start Time	Between 16 weeks, 0 days and 20 weeks, 6 days of gestation
End Time	Until week 37 (through 36 weeks, 6 days) of gestation or delivery, whichever occurs first

It is essential to rotate the injection site each week (alternating buttocks) to minimize local reactions. The injection, due to the oily nature of the solution, is generally administered slowly (over one minute or longer) by a qualified professional. You must not miss a dose and should contact your doctor immediately if a dose is missed.

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Important Considerations

• Patient Training: If self-administration is necessary, rigorous training by a healthcare professional on proper preparation, sterile technique, and intramuscular injection procedure is mandatory.
• Inspection: The solution must be clear and yellow; do not use if particles or discoloration are present.
• Storage: Store at room temperature (typically 20 C to 25 C or 68 F to 77 F). Do not refrigerate or freeze.

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Note: In some regions, the overall benefit-risk balance of 17-OHPC medicines has been re-evaluated, leading to recommendations for their suspension in certain indications. Always follow the most current advice and prescription instructions from your healthcare provider.

Research evidence / Overview of studies for Lentogest

Evidence for Use in Luteal Phase Support

This section will summarize the available clinical research, primarily focusing on Randomized Controlled Trials (RCTs) and systematic reviews, that examined the effects of hydroxyprogesterone caproate (HPC) during the luteal phase, often in the context of assisted reproductive technologies.

Lentogest was studied in populations of women undergoing fertility treatments, such as those receiving in vitro fertilization (IVF). Researchers measured major outcomes like the Live Birth Rate (LBR), Clinical Pregnancy Rate, and the overall Miscarriage Rate in the study populations. Studies reported measurements of physiological changes, such as those related to the uterine lining. Comparative evidence is lacking for this specific formulation against other forms of progesterone.

Conflicting Evidence and Regulatory Status for Recurrent Preterm Birth

This critical section will describe the significant body of research, including large, modern clinical trials, that investigated the use of HPC in women at risk of recurrent spontaneous preterm birth. It will specifically summarize the conflicting findings from major studies.

Initial studies explored whether there was an association with a change in the rate of spontaneous delivery before 37 weeks of gestation in women who had previously delivered early. However, the most recent and largest confirmatory RCT did not report the same measurements for the primary outcome that had been observed in earlier studies. Following this review, major governmental regulators, including the U.S. FDA, made the decision to formally withdraw approval for this indication. This situation highlights that evidence quality varies across studies, and the certainty remains low regarding the use of HPC in the clinical context of recurrent preterm birth.

Evidence for Amenorrhea and Abnormal Uterine Bleeding

The research record for HPC related to the clinical context of the absence of menstruation (amenorrhea) and certain types of abnormal uterine bleeding relies on historical regulatory data and older efficacy studies. Studies monitored the ability to induce withdrawal uterine bleeding and to observe the patterns of the menstrual cycle. The evidence is limited, as it largely consists of older, non-modern clinical trials. Sample sizes were modest in some of these older trials. Follow-up durations were limited, and comparative evidence is lacking regarding how this medicine performs against modern treatment options.

What is Still Uncertain in the Research Record

The biggest uncertainty concerns the conflicting findings for use in women at risk of recurrent preterm birth, which has led to major regulatory divergence. Across all indications, long-term effects are not fully established and data are still emerging regarding developmental outcomes for children exposed to the medicine during pregnancy. Overall, research highlights what is known—and what is still uncertain—and data for certain groups remain insufficient.

Key Studies & References Evaluation of Amenorrhea, Anovulation, and Abnormal Bleeding (Authoritative clinical guidance used for general indication context)

Common questions about Lentogest (FAQ)

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Q: How long does a dose of Lentogest work for?

Lentogest is formulated as a long-acting, or 'depot,' injection, and is administered once every seven days according to product information. Pharmacokinetic studies have indicated that, following an injection, the maximum concentration of the drug in the blood is generally reached within a window of three to seven days.

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Q: What specific types of abnormal uterine bleeding is Lentogest used to treat?

According to regulatory documents, this medication is indicated for specific hormonal support in non-pregnant women. The drug is indicated for the treatment of the absence of menstruation (amenorrhea) and abnormal uterine bleeding that is caused by hormonal imbalance, where other organic causes have been ruled out.

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Q: Is Lentogest the same thing as the natural hormone progesterone?

No, Lentogest is a synthetic hormone called hydroxyprogesterone caproate (17-OHPC). It is classified as a progestogen, which is a man-made compound designed to mimic the action of the body's natural progesterone hormone. Its specific chemical structure allows for its long-acting profile.

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Q: Can I self-inject Lentogest at home?

Official drug labeling and safety information state that this medication should not be self-administered. It is required to be given by or under the direct supervision of a qualified healthcare provider.

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Q: What should I do if the injection site is hard or lumpy a day later?

Injection site reactions such as pain, swelling, and the formation of small lumps (nodules) are common adverse reactions noted in official safety information. However, official safety information states that increasing pain, excessive swelling, or oozing of blood or fluid at the site are reasons to seek immediate medical attention from your healthcare provider.

How to Store and Dispose of Hydroxyprogesterone Caproate Injection

Official regulatory documentation outlines specific storage and disposal requirements to maintain the product's stability and ensure safe handling.

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Storage Requirements

• Temperature: Store at Controlled Room Temperature, defined as 20 to 25 C (68 to 77 F). Do not refrigerate or freeze the solution.
• Protection: The vial must be kept in its original carton to protect the contents from light and moisture.
• Stability: If a multi-dose vial is used, any unused portion must be discarded 28 days after the first puncture.
• Child Safety: The medication must be stored out of the sight and reach of children.

Disposal Instructions

Used needles and syringes must be placed immediately in an FDA-cleared sharps disposal container. Any expired or unused product must be disposed of according to local, regional, and national regulations; do not dispose of the medication via household trash or wastewater systems.