Dienogest

How it works

It exerts a strong progestogenic effect on the endometrium and downregulates ovarian oestrogen production, inducing decidualisation and atrophy of ectopic endometriotic tissue.

Prescribing in practice

• Irregular or unscheduled vaginal bleeding is common, especially early on; investigate any new or persistent unexpected bleeding to exclude other pathology.
• Long-term progestogen exposure may reduce bone mineral density, so weigh this in younger women and those with additional risk factors.
• It is not a licensed contraceptive in this indication, so advise non-hormonal contraception, and avoid in active venous thromboembolism and known or suspected hormone-dependent malignancy.

Monitoring

Review symptom control and bleeding patterns, monitor blood pressure, and consider bone health with prolonged use.

Counselling the patient

• Irregular bleeding or spotting is common and usually settles with continued use.
• Use a non-hormonal method of contraception while taking it.
• Report any persistent or heavy unexpected bleeding.

Evidence & guidelines

Dienogest is an established second-line therapy for endometriosis-associated pain, recognised within NICE endometriosis guidance among hormonal treatment options.