Overview
Dydrogesterone is a synthetic progestogen used primarily in gynecological conditions. It is structurally similar to natural progesterone but has greater oral bioavailability and selectivity for progesterone receptors. Unlike many other progestogens, dydrogesterone has minimal androgenic, estrogenic, glucocorticoid, or mineralocorticoid activity, making it well-tolerated for various hormone-related disorders.
Mechanism of Action
Dydrogesterone is a selective progesterone receptor agonist. It binds to progesterone receptors in the endometrium, inducing secretory changes and supporting the luteal phase of the menstrual cycle. It does not inhibit ovulation at therapeutic doses and has minimal effects on other steroid receptors, reducing side effects like androgenic or glucocorticoid activity.
Indications
- Endometriosis
- Dysfunctional uterine bleeding
- Secondary amenorrhea
- Premenstrual syndrome (PMS)
- Infertility due to luteal insufficiency
- Hormone replacement therapy (HRT) in combination with estrogen for menopausal symptoms
- Threatened or habitual abortion (to support pregnancy)
- Irregular menstrual cycles
Dosage
Dosage varies by indication: For menstrual disorders (e.g., irregular cycles, PMS): 10 mg twice daily from day 11 to day 25 of the cycle. For endometriosis: 10 mg two to three times daily. For infertility/luteal support: 10 mg twice daily from day 14 to day 25 of the cycle, continued into early pregnancy if needed. For HRT: Typically 10 mg daily for 14 days per 28-day cycle alongside estrogen. Always follow physician instructions; adjustments may be based on response.
Contraindications
- Known hypersensitivity to dydrogesterone or any component of the formulation
- Undiagnosed vaginal bleeding
- Severe liver dysfunction or hepatic tumors
- History of or active thromboembolic disorders (e.g., deep vein thrombosis, pulmonary embolism)
- Porphyria
- Suspected or known progesterone-dependent neoplasms (e.g., meningioma)
Side Effects
- Headache
- Nausea
- Breast tenderness or pain
- Breakthrough bleeding or spotting
- Abdominal pain or bloating
- Dizziness
- Fatigue
- Mood changes (e.g., depression, irritability)
- Skin reactions (e.g., rash, pruritus)
- Weight changes
- Rarely: thromboembolic events, hepatic dysfunction, allergic reactions
Interactions
- Enzyme inducers (e.g., rifampicin, phenytoin, carbamazepine) may reduce dydrogesterone efficacy by increasing metabolism.
- No significant interactions with common drugs like anticoagulants or antihypertensives reported, but monitor with concurrent therapies.
- Potential additive effects with other progestogens or hormonal agents.