Dienogest: Progestin for Endometriosis
Dienogest is a synthetic progestogen with high selectivity for progesterone receptors and anti-androgenic properties. It has a unique dual mechanism — progestogenic and anti-estrogenic — making it particularly effective for endometriosis treatment.
Approved for endometriosis (monotherapy) in Europe, Japan, and Australia. Also used in combined oral contraceptives (with oestradiol valerate: Qlaira/Natazia). Creates a hypoestrogenic, hyperprogestogenic environment that inhibits endometrial growth.
Mechanism of Action
Strong progesterone receptor agonist with anti-androgenic activity. Suppresses LH secretion (reducing ovarian oestrogen production), directly inhibits endometrial cell proliferation and induces decidualisation, and reduces local oestrogen biosynthesis in endometriotic tissue. Minimal glucocorticoid/mineralocorticoid effects.
Indications & Use
Endometriosis (treatment of pain and reduction of lesions). Not a contraceptive when used as monotherapy (though it suppresses ovulation in most women). Combined oral contraceptive with oestradiol valerate (Qlaira) for contraception and heavy menstrual bleeding.
Dosage
Endometriosis: 2 mg once daily continuously (no breaks). Start on day 1–5 of cycle or immediately if pregnancy excluded. Treatment duration up to 15 months studied; clinical guidelines often recommend re-evaluation after 6 months.
Side Effects
Common: irregular uterine bleeding/spotting (especially first months), headache, depressed mood, breast discomfort. Hypoestrogenic effects: decrease in bone mineral density (BMD) with long-term use — monitor if >6 months. Weight changes, acne.
Drug Interactions
CYP3A4 inducers (rifampicin, carbamazepine, phenytoin, St John's Wort): reduce dienogest levels. CYP3A4 inhibitors (ketoconazole, erythromycin): increase levels. No clinically significant effects with most common medications.
Contraindications
Pregnancy, undiagnosed genital bleeding, current or past arterial/venous thromboembolic disease, severe hepatic disease, sex hormone-dependent tumours.
Frequently Asked Questions
Does dienogest protect against pregnancy?
Dienogest 2 mg monotherapy is not a reliable contraceptive. While it suppresses ovulation in most women, the contraceptive protection is insufficient. Barrier contraception is recommended. The combined pill Qlaira (oestradiol valerate/dienogest) provides reliable contraception.
How long does dienogest take to work for endometriosis?
Pain relief is typically experienced within 1–3 months. Objective reduction in lesion size occurs over 6 months. Treatment is continuous — taking breaks may lead to symptom return. Most patients notice significant improvement by month 3.
What happens to bones with long-term dienogest?
Dienogest reduces oestrogen levels, which can decrease bone mineral density. BMD loss reverses after stopping dienogest. For use beyond 6 months, vitamin D and calcium supplementation and BMD monitoring are recommended, especially in young women.
References
- EMA Visanne SPC 2023
- ESHRE Endometriosis Guideline 2022
- Strowitzki T et al. Hum Reprod 2010
Medical Disclaimer: This information is for educational purposes only and does not replace professional medical advice.