BMA Concise Guide to Medicine & Drugs

Dydrogesterone

Brand name None

Used in the following combined preparations Femapak, Femoston 1/10 and 2/10, Femoston-conti

QUICK REFERENCE

Drug group Female sex hormone

Overdose danger rating Low

Dependence rating Low

Prescription needed Yes

Available as generic No

GENERAL INFORMATION

Dydrogesterone is a synthetic version of the natural female sex hormone progesterone that has more specific hormonal effects and greater potency than progesterone itself. The drug is no longer used alone but is still available together with an oestrogen as part of hormone replacement therapy (HRT) following the menopause. Dydrogesterone is added either to each HRT tablet (continuous combined HRT) or only the tablets taken during the second half of each 28-day cycle (cyclical HRT). Only cyclical HRT produces regular shedding of the lining of the uterus, mimicking a period. However, both types prevent the risk of endometrial cancer in women on HRT who have an intact uterus.

INFORMATION FOR USERS

Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.

How taken/used Tablets.

Frequency and timing of doses Once daily.

Adult dosage range 5–10mg daily in combined preparations.

Onset of effect Beneficial effects of this drug may not be felt for several months.

Duration of action 12–24 hours.

Diet advice None.

Storage Keep in original container at room temperature out of the reach of children. Protect from light.

Missed dose Take as soon as you remember. If your next dose is due within 2 hours, take a single dose now and skip the next.

Stopping the drug Take as soon as you remember. If more than 24 hours have elapsed, do not take the missed tablet and take the next tablet at the normal time. Missed doses may increase the risk of irregular bleeding or spotting.

Exceeding the dose An occasional unintentional extra dose is unlikely to be a cause for concern. But if you notice any unusual symptoms, or if a large overdose has been taken, notify your doctor.

POSSIBLE ADVERSE EFFECTS

Irregular periods and breakthrough bleeding are the most common adverse effects of dydrogesterone. These symptoms may be helped by adjusting the dosage of the drug. Other common adverse effects include swelling of the feet or ankles, rash, and weight gain. More rarely, the drug may cause nausea, vomiting, and breast tenderness. Talk to your doctor if any of these symptoms become severe or if the drug causes headache or dizziness.

INTERACTIONS

Anticonvulsants Some of these drugs may reduce the effect of dydrogesterone, and dydrogesterone may reduce the effect of lamotrigine.

Ciclosporin Dydrogesterone increases the effects of this drug.

St. John’s wort may reduce the effect of dydrogesterone.

SPECIAL PRECAUTIONS

Be sure to tell your doctor if:

· You have a long-term liver or kidney problem.

· You have heart or circulatory problems, especially a history of venous or pulmonary thrombosis.

· You have diabetes.

· You have high blood pressure.

· You have porphyria.

· You or a family member have had breast cancer.

· You are taking other medicines.

Pregnancy Not used. If you become pregnant, stop the drug immediately and contact your doctor.

Breast-feeding Not used.

Infants and children Not prescribed.

Over 60 No special problems.

Driving and hazardous work Avoid such activities until you have learned how dydrogesterone affects you because the drug may rarely cause dizziness.

Alcohol No special problems.

PROLONGED USE

As part of HRT, dydrogesterone is usually only advised for short-term use after the menopause. It is not normally recommended for long-term use or for treating osteoporosis. HRT increases the risk of both venous thrombosis and breast cancer. This risk diminishes after stopping the drug, disappearing entirely after 10 years.

Monitoring Blood-pressure checks and physical examinations, including regular mammograms, may be performed.