Usage
Dydrogesterone is a progestogen, a synthetic hormone similar to progesterone. It’s prescribed for conditions related to progesterone deficiency:
- Menstrual Disorders: Dysmenorrhea (painful periods), irregular cycles, premenstrual syndrome (PMS), dysfunctional uterine bleeding (DUB), and secondary amenorrhea (absence of periods).
- Infertility: Luteal phase support in assisted reproductive technology (ART) and treatment of infertility due to luteal insufficiency.
- Pregnancy Complications: Threatened and habitual miscarriage (associated with progesterone deficiency).
- Endometriosis: Management of symptoms.
- Hormone Replacement Therapy (HRT): Combined with estrogen to prevent endometrial hyperplasia.
Alternate Names
- International Nonproprietary Name (INN): Dydrogesterone
- Brand Names: Duphaston, Dabroston, Dydrogest, and others (vary by region).
How It Works
Pharmacodynamics: Dydrogesterone selectively binds to progesterone receptors in the uterus, inducing secretory changes in the endometrium. Unlike some progestogens, it doesn’t have androgenic, estrogenic, or glucocorticoid activity. It doesn’t inhibit ovulation.
Pharmacokinetics:
- Absorption: Rapid oral absorption with peak plasma levels in 0.5 to 2.5 hours.
- Metabolism: Primarily metabolized in the liver to dihydrodydrogesterone (DHD), mainly by CYP3A4.
- Elimination: Excreted mainly in urine, with a small amount in feces.
Mode of Action: Binds to progesterone receptors, modulating gene expression and inducing a secretory endometrium, essential for implantation and maintaining pregnancy.
Dosage
Standard Dosage
Adults: Dosage varies depending on the indication. Common dosages include 10 mg once or twice daily, sometimes up to 30 mg daily in divided doses. Timing of administration depends on the specific condition (e.g., during the luteal phase for menstrual disorders, continuously during early pregnancy for threatened miscarriage).
Children: Dydrogesterone isn’t recommended for use in children under 18 years of age. Safety and efficacy haven’t been established in this population.
Special Cases:
- Elderly Patients: No specific dosage adjustments are typically required, but caution is advised due to potential age-related decline in liver and kidney function.
- Patients with Renal Impairment: Caution is advised. Dose adjustment might be necessary.
- Patients with Hepatic Dysfunction: Use with caution, as Dydrogesterone is primarily metabolized in the liver. Dose adjustments may be required.
- Patients with Comorbid Conditions: Caution is advised in patients with conditions like diabetes, cardiovascular disease, depression, and history of thromboembolic events.
Clinical Use Cases
Dydrogesterone isn’t typically used in acute clinical settings like intubation, surgical procedures, mechanical ventilation, ICU use, or emergency situations. It’s primarily used for chronic hormonal management.
Dosage Adjustments
Adjustments may be necessary based on individual patient response and tolerability. Careful consideration should be given to patients with renal or hepatic impairment. Drug interactions can also influence dosage.
Side Effects
Common Side Effects:
- Headache, migraine
- Nausea
- Breast tenderness/pain
- Menstrual irregularities (breakthrough bleeding, spotting)
- Abdominal pain, bloating
Rare but Serious Side Effects:
- Allergic reactions (rash, itching, swelling)
- Venous thromboembolism (VTE) - though a direct causal relationship with dydrogesterone hasn’t been established, caution is necessary, especially in patients with risk factors.
- Liver dysfunction (rare)
Long-Term Effects:
Limited data available on long-term effects. Some studies suggest a potential, though not definitive, increased risk of breast cancer with long-term HRT that includes progestogens.
Adverse Drug Reactions (ADR):
Severe allergic reactions require immediate medical attention. Signs may include difficulty breathing, swelling of face/throat, and severe rash.
Contraindications
- Hypersensitivity to dydrogesterone
- Undiagnosed vaginal bleeding
- Known or suspected progestogen-dependent neoplasms
- Severe liver dysfunction
- Active thromboembolic disorders
- Breast cancer (current or history)
Drug Interactions
Dydrogesterone is metabolized by CYP3A4. Drugs that induce or inhibit CYP3A4 can affect its levels. These include:
- CYP3A4 Inducers: Rifampicin, phenytoin, carbamazepine, St. John’s Wort - can decrease dydrogesterone levels.
- CYP3A4 Inhibitors: Ketoconazole, itraconazole, erythromycin - can increase dydrogesterone levels.
- Some hormonal contraceptives
- Anticoagulants
Pregnancy and Breastfeeding
- Pregnancy: Dydrogesterone is often used in pregnancy to support the luteal phase and prevent miscarriage in those with a history of or at risk for pregnancy loss. While generally considered safe, it’s crucial to weigh the potential risks and benefits. No conclusive evidence of teratogenicity exists.
- Breastfeeding: Small amounts of dydrogesterone are excreted in breast milk. Its safety during breastfeeding hasn’t been definitively established. It’s advisable to avoid use or consider alternative options if possible.
Drug Profile Summary
- Mechanism of Action: Selective progesterone receptor agonist in the uterus.
- Side Effects: Headache, nausea, breast tenderness, menstrual irregularities. Rarely, allergic reactions or liver dysfunction.
- Contraindications: Hypersensitivity, undiagnosed vaginal bleeding, progestogen-dependent tumors, liver dysfunction.
- Drug Interactions: CYP3A4 inducers/inhibitors, some hormonal contraceptives, anticoagulants.
- Pregnancy & Breastfeeding: Generally considered safe in pregnancy for indicated conditions. Use with caution during breastfeeding.
- Dosage: Varies depending on indication. Commonly 10-20 mg daily.
- Monitoring Parameters: Liver function tests (if indicated), monitor for signs of allergic reactions or thromboembolic events.
Popular Combinations
Often combined with estrogen in hormone replacement therapy.
Precautions
- Evaluate liver function in patients with hepatic impairment.
- Assess risk factors for thromboembolic events.
- Monitor patients with a history of depression.
- Patients with rare hereditary problems of galactose intolerance, the Lapp lactase deficiency or glucose-galactose malabsorption should not take this medicine.
FAQs (Frequently Asked Questions)
Q1: What is the recommended dosage for Dydrogesterone?
A: It depends on the indication. For menstrual irregularities, it might be 10-20 mg daily during the luteal phase. For threatened miscarriage, an initial dose of 40 mg followed by 10 mg every 8 hours might be prescribed.
Q2: Can Dydrogesterone be used during pregnancy?
A: Yes, it’s often used to support pregnancy in women with a history of miscarriage or luteal phase deficiency.
Q3: Is Dydrogesterone safe while breastfeeding?
A: Limited data are available. Small amounts are excreted in breast milk. Discuss with a physician to weigh the risks and benefits.
Q4: What are the common side effects of Dydrogesterone?
A: Headache, nausea, breast tenderness, and menstrual irregularities are common.
Q5: Does Dydrogesterone interact with other medications?
A: Yes, it interacts with drugs that affect CYP3A4 enzyme activity.
Q6: Can Dydrogesterone cause blood clots?
A: A direct causal link hasn’t been definitively established, but caution is advised, especially in patients with pre-existing risk factors for VTE.
Q7: What should I do if I miss a dose of Dydrogesterone?
A: Take the missed dose as soon as remembered, unless it’s close to the next dose. Don’t double the dose.
Q8: How long does it take for Dydrogesterone to work?
A: The onset of action varies depending on the condition being treated.
Q9: Can Dydrogesterone be used in children?
A: No, it is not recommended for children under 18.
This information is current as of February 16, 2025. Medical knowledge is constantly evolving, so it’s always best to consult with a qualified healthcare professional for the most up-to-date information and personalized advice.
