BMA Concise Guide to Medicine & Drugs

Desogestrel

Brand name Cerazette

Used in the following combined preparations Gedarel, Marvelon, Mercilon

QUICK REFERENCE

Drug group Female sex hormone and oral contraceptive

Overdose danger rating Low

Dependence rating Low

Prescription needed Yes

Available as generic No

GENERAL INFORMATION

Desogestrel is a synthetic hormone that is similar to the natural female sex hormone progesterone. It is used alone as a progestogen-only pill, or ‘POP’ and is especially helpful as contraception in women who do not tolerate oestrogens or are breast-feeding. Desogestrel works by thickening the mucus at the neck of the cervix, making it difficult for sperm to enter. Unlike other POPs, the drug also works by preventing ovulation (release of an egg from the ovary). In addition, it changes the quality of the endometrium (lining of the uterus), preventing implantation of a fertilized egg.

Desogestrel is also used in combination with the oestrogen drug ethinylestradiol as an oral contraceptive.

When desogestrel is taken without an oestrogen, irregular vaginal bleeding may occur in the form of slight spotting, heavier bleeding, or no bleeding at all. Desogestrel, either alone or in a combined oral contraceptive, also carries a significant risk of venous thrombosis.

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 One tablet at the same time each day.

Adult dosage range 75mcg daily.

Onset of effect Within a few hours.

Duration of action 24 hours.

Diet advice None.

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

Missed dose If a tablet is delayed by 12 hours or more, regard it as a missed pill. See What to do if you miss a pill.

Stopping the drug The drug can be safely stopped as soon as contraceptive protection is no longer required. For treatment of menstrual symptoms, consult your doctor before stopping the drug.

Exceeding the dose An occasional unintentional 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 vaginal bleeding is the most common side effect of desogestrel taken alone. If you experience heavy or prolonged bleeding, consult your doctor. Other common side effects include nausea, vomiting, headache, breast discomfort or tenderness, weight changes, and mood changes. More rarely, the drug may cause changes in skin pigmentation. If any of these symptoms becomes severe, discuss with your doctor.

INTERACTIONS

General note The beneficial effects of many drugs, including oral anticoagulants, anticonvulsants, and antihypertensive and drugs for diabetes, may be affected by desogestrel. Many other drugs may reduce the contraceptive effect of desogestrel. These include anticonvulsants, antituberculous drugs, antidepressants, and the herbal remedy St John’s wort.

SPECIAL PRECAUTIONS

Be sure to tell your doctor if:

· You have a liver problem.

· You have diabetes.

· You have jaundice.

· You have had an ectopic pregnancy.

· You have unexplained abnormal vaginal bleeding.

· You have had epileptic seizures.

· You have had venous thrombosis or a stroke.

· You are taking other medicines.

Pregnancy Not prescribed. May cause defects in the developing baby. Discuss with your doctor.

Breast-feeding The drug passes into the breast milk, but at normal doses adverse effects on the baby are unlikely. Discuss with your doctor.

Infants and children Not prescribed.

Over 60 Not prescribed.

Driving and hazardous work No known problems.

Alcohol No known problems.

PROLONGED USE

There is a small increase in the risk of breast cancer in women who have used a progestogen-only pill. However, the risk is related to the age at which the pill is stopped rather than duration of use. The increased risk reduces to zero over 10 years after stopping use.

Monitoring Regular blood pressure checks may be carried out.