1. Clinical Overview
Progesterone (Natural Micronized) 200mg is a bioidentical hormone preparation used for hormone replacement therapy (HRT) and other gynecological conditions. The micronization process increases the surface area of the progesterone particles, significantly enhancing its oral bioavailability without the need for chemical modification. It is derived from plant sources (typically diosgenin from yams or soy) and is structurally identical to endogenous human progesterone.
| Onset | Duration | Bioavailability |
|---|---|---|
| Oral: 1-2 hours for peak plasma concentration. Vaginal: Variable, systemic absorption occurs over several hours. | Approximately 24 hours, requiring once or twice-daily dosing to maintain therapeutic levels. | Oral: Approximately 10-15% due to extensive first-pass metabolism. Vaginal: Variable but higher local endometrial concentration with lower systemic levels compared to oral route. |
2. Mechanism of Action
Progesterone is the principal endogenous progestogen. It binds to and activates the intracellular progesterone receptor (PR-A and PR-B isoforms) in target tissues (uterus, breast, brain). The hormone-receptor complex translocates to the nucleus, binds to specific progesterone response elements (PREs) on DNA, and modulates gene transcription, leading to characteristic progestogenic effects.
3. Indications & Uses
- Secondary amenorrhea
- Dysfunctional uterine bleeding (DUB)
- Luteal phase support in Assisted Reproductive Technology (ART) and Infertility treatment
- Hormone Replacement Therapy (HRT) in postmenopausal women with an intact uterus (combined with estrogen)
4. Dosage & Administration
Adult Dosage: **Amenorrhea/DUB:** 200-400 mg daily in single or divided doses for 10-12 days. **HRT (cyclic):** 200 mg daily for the last 12-14 days of each estrogen cycle. **HRT (continuous):** 100-200 mg daily continuously with estrogen. **ART/Luteal Support:** 200-600 mg daily in 2-3 divided doses, starting after oocyte retrieval/embryo transfer and continuing for up to 10-12 weeks of pregnancy. Vaginal administration is common for this indication.
Administration: **Oral:** Take with food to improve absorption and reduce dizziness/drowsiness. Preferably at bedtime. Swallow capsule whole. **Vaginal:** Insert deeply into the vagina, usually once or twice daily as prescribed. Can be used in combination with oral therapy in ART. Do not use if capsule is leaking. Wash hands before and after administration.
5. Side Effects
Common side effects may include:
- Drowsiness, dizziness, sedation
- Headache
- Breast tenderness/pain
- Bloating, abdominal cramping
- Mood swings, irritability
- Breakthrough bleeding/spotting
- Fatigue
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Ketoconazole, Itraconazole, Clarithromycin | Inhibit CYP3A4, increasing progesterone levels and risk of side effects. | Major |
| Rifampicin, Carbamazepine, Phenytoin, St. John's Wort | Induce CYP3A4, decreasing progesterone efficacy. | Major |
| Other CNS depressants (Alcohol, Benzodiazepines, Opioids) | Additive sedative effect, increased drowsiness and impairment. | Moderate |
| Enzyme inducers (e.g., Barbiturates) | May reduce progesterone effectiveness. | Moderate |
| Drugs affecting blood clotting (Warfarin) | Progesterone may alter anticoagulant response; monitor INR closely. | Moderate |
7. Patient Counselling
- DO take the medication exactly as prescribed, at the same time(s) each day.
- DO take oral capsules with food, preferably at bedtime if drowsiness occurs.
- DO use a reliable non-hormonal method of contraception if not trying to conceive, as progesterone is not a reliable contraceptive.
- DO report any unusual vaginal bleeding immediately.
- DONT stop taking the medication abruptly without consulting your doctor.
- DONT drink alcohol while on this medication.
- DONT take other medicines (including herbal supplements like St. John's Wort) without informing your doctor.
8. Toxicology & Storage
Overdose: Symptoms are an extension of side effects: severe drowsiness, dizziness, nausea, vomiting. No specific life-threatening acute overdose syndrome reported.
Storage: Store below 25°C, in a cool, dry place. Protect from light and moisture. Keep out of reach of children. Do not use if the capsule is damaged or leaking.