Geston

• Prevention of Preterm Labor and Threatened Miscarriage: Used to support pregnancy in women with a history or risk of habitual abortion or threatened miscarriage.
• Management of Menstrual Disorders: Treatment of irregular menstrual cycles or secondary amenorrhea caused by progesterone deficiency.
• Treatment of Prostatic Hypertrophy: Occasionally used in men to alleviate symptoms of benign prostatic hypertrophy due to its progestogenic activity.
• Off-label/Clinically Accepted Uses:
• Hormonal support in assisted reproductive technology (ART) protocols.
• Adjunct therapy in certain gynecological disorders related to luteal phase defects.

• Adults (Women):
• For prevention of threatened miscarriage or habitual abortion: 5–10 mg orally 2–3 times daily, depending on physician’s guidance.
• Duration: Typically throughout the first trimester or as prescribed.
• Adults (Men):
• For prostatic hypertrophy: 10 mg orally 3 times daily; duration based on clinical response.
• Pediatrics: Not established; not recommended.
• Elderly: Use with caution; dose adjustment may be necessary depending on indication.
• Special Populations:
• No specific dosage adjustment recommended for hepatic or renal impairment, but caution advised.
• Administration: Oral tablets; taken with or without food.

Allylestrenol is a synthetic progestogen structurally related to 19-nortestosterone derivatives. It exerts progestational effects by binding to progesterone receptors in the uterus and other reproductive tissues, promoting endometrial stability and suppressing uterine contractions. This hormonal support helps maintain pregnancy and regulates menstrual cycle irregularities. Unlike some other progestins, allylestrenol exhibits minimal androgenic, estrogenic, or glucocorticoid activity.

• Absorption: Rapid and almost complete oral absorption; peak plasma concentrations reached within 2–4 hours.
• Distribution: Widely distributed; protein binding is moderate.
• Metabolism: Extensively metabolized in the liver via reduction and hydroxylation.
• Half-life: Approximately 10–14 hours.
• Elimination: Primarily excreted in urine as inactive metabolites.

• Pregnancy: Category B (FDA classification) or no well-controlled studies but widely used in pregnancy for luteal support; generally considered safe when prescribed appropriately.
• Lactation: Limited data; use with caution as it may pass into breast milk; benefits vs. risks should be assessed.

• Primary Class: Progestogen
• Subclass: Synthetic progestin, 19-nor derivative

• Known hypersensitivity to allylestrenol or any component of the formulation.
• Active or history of thromboembolic disorders.
• Undiagnosed vaginal bleeding.
• Hormone-sensitive cancers (e.g., breast, endometrial).
• Severe liver dysfunction.

• Monitor for thromboembolic events, especially in women with risk factors.
• Use cautiously in patients with liver disease or history of hormone-sensitive tumors.
• May mask symptoms of estrogen-dependent cancers; regular screening advised.
• Not recommended as a contraceptive method.
• Monitor blood pressure and metabolic parameters during prolonged use.

• Common:
• Menstrual irregularities, spotting, or breakthrough bleeding.
• Headache, dizziness.
• Breast tenderness.
• Less common:
• Nausea, fatigue.
• Mood changes or depression.
• Rare/Serious:
• Thromboembolic events (deep vein thrombosis, pulmonary embolism).
• Allergic reactions including rash or angioedema.

• Enzyme Inducers (e.g., rifampicin, phenytoin, carbamazepine): May reduce allylestrenol efficacy by increasing metabolism.
• CYP3A4 inhibitors: Potentially increase plasma levels, enhancing effects and adverse reactions.
• Other hormonal agents: Additive hormonal effects possible; monitor accordingly.
• Alcohol and other CNS depressants: May potentiate CNS effects like dizziness.

• Recent obstetric guidelines support the use of allylestrenol for luteal phase support and prevention of miscarriage in select populations.
• Updated safety reviews emphasize cautious use in patients with thromboembolic risk.
• No major changes in dosing; emphasis on individualized therapy and monitoring.

• Store at 20°C to 25°C (68°F to 77°F).
• Protect from moisture and light.
• Keep tablets in original packaging until use.
• Do not freeze.
• Keep out of reach of children.