1. Clinical Overview
Dienogest is a fourth-generation, hybrid progestogen with a unique pharmacological profile. It is a 19-nortestosterone derivative that exhibits high selectivity for the progesterone receptor with minimal androgenic, estrogenic, glucocorticoid, or mineralocorticoid activity. In the Indian context, it is primarily used for the long-term management of endometriosis-associated pain and as a progestogen-only component in combined oral contraceptives (COCs). Its anti-proliferative, anti-inflammatory, and anti-angiogenic effects on endometrial tissue make it a cornerstone therapy for endometriosis.
| Onset | Duration | Bioavailability |
|---|---|---|
| Pharmacodynamic effects (e.g., ovulation inhibition) begin within the first few days of administration, but full therapeutic benefit for endometriosis pain relief may take 2-3 months. | Approximately 24 hours, supporting once-daily dosing. | Approximately 91% following oral administration. |
2. Mechanism of Action
Dienogest exerts its therapeutic effects through a strong, selective binding to the progesterone receptor. In endometriosis, it creates a hypo-estrogenic, hyper-progestogenic environment by suppressing the hypothalamic-pituitary-ovarian (HPO) axis, leading to anovulation and reduced endogenous estrogen production. This inhibits the growth and viability of ectopic endometrial implants. It also has direct anti-proliferative, anti-inflammatory, and anti-angiogenic effects on endometrial tissue.
3. Indications & Uses
- Long-term management of endometriosis-associated pain (as monotherapy 2mg once daily)
- Hormonal contraception (in combination with Ethinylestradiol, e.g., in Valni, Divaa ED)
4. Dosage & Administration
Adult Dosage: For Endometriosis: 2mg orally once daily, taken continuously (without a pill-free interval) starting on any day of the cycle. For Contraception (in combination pills): As per the specific brand's regimen, typically one tablet daily for 21-24 days followed by a 4-7 day hormone-free interval.
Administration: Take at approximately the same time each day, with or without food. If a dose is missed by less than 12 hours, take it immediately and continue the normal schedule. If missed by more than 12 hours, the efficacy for contraception may be reduced (for COCs); for endometriosis, take the missed pill and continue normally. Use additional non-hormonal contraception (condoms) for the next 7 days if used for contraception and a pill is missed.
5. Side Effects
Common side effects may include:
- Headache
- Breast pain/discomfort
- Nausea
- Acne
- Weight increase
- Mood changes (depressed mood, mood swings)
- Abdominal pain
- Irregular uterine bleeding (spotting, breakthrough bleeding) especially in first 3-4 months
6. Drug Interactions
| Drug | Effect | Severity |
|---|---|---|
| Enzyme Inducers (e.g., Rifampicin, Rifabutin, Phenytoin, Carbamazepine, Phenobarbital, St. John's Wort) | Significantly reduces Dienogest plasma levels, leading to decreased efficacy and increased breakthrough bleeding. May cause contraceptive failure. | Major |
| HIV Protease Inhibitors (e.g., Ritonavir) | May alter Dienogest metabolism; data is conflicting. Can potentially increase or decrease levels. | Moderate |
| Antibiotics (e.g., Ampicillin, Tetracyclines) | Theoretical risk of reduced efficacy due to altered gut flora affecting enterohepatic circulation. Evidence is limited but caution advised. | Moderate |
| Lamotrigine | Dienogest may decrease Lamotrigine plasma levels, potentially reducing seizure control. | Major |
7. Patient Counselling
- DO take the tablet at the same time every day for best results.
- DO use additional barrier contraception (condoms) for 7 days if you miss a pill (for contraceptive use) or start a new pack late.
- DO inform any new doctor or surgeon that you are taking Dienogest.
- DONT smoke, especially if you are over 35 years old, as it drastically increases cardiovascular risks.
- DONT take the medicine if you are pregnant or suspect pregnancy.
- DONT stop taking the medicine for endometriosis without consulting your doctor, even if you feel better.
8. Toxicology & Storage
Overdose: No serious sequelae have been reported following acute overdose. Symptoms may include nausea, vomiting, and slight vaginal bleeding. In young children, accidental ingestion may cause estrogenic effects.
Storage: Store below 30°C. Protect from light and moisture. Keep in the original blister pack until use. Keep out of reach and sight of children.