BMA Concise Guide to Medicine & Drugs

Levonorgestrel

Brand names Levonelle 1500, Levonelle One Step, Mirena, Norgeston

Used in the following combined preparations Cyclo-progynova, Logynon ED, Microgynon 30, Ovranette, and others

QUICK REFERENCE

Drug group Female sex hormone and oral contraceptive

Overdose danger rating Low

Dependence rating Low

Prescription needed Yes (most preparations)

Available as generic No

GENERAL INFORMATION

Levonorgestrel is a synthetic hormone similar to progesterone, a natural female sex hormone. Its primary use is in oral contraceptives. It performs this function by thickening the mucus at the neck of the uterus (cervix), thereby making it difficult for sperm to enter the uterus.

Levonorgestrel is available in combined oral contraceptives (COCSs) with an oestrogen drug. It is also given, in a higher dose, as a progestogen-only preparation (POP), for emergency, postcoital contraception and can be obtained over the counter by women over the age of 16. It is also combined with an oestrogen drug in hormone replacement therapy (HRT) for the short-term treatment of menopausal symptoms.

The drug rarely causes serious adverse effects. When it is used alone, menstrual irregularities, especially mid-cycle, or “breakthrough”, bleeding may occur.

INFORMATION FOR USERS

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

How taken/used Tablets, intrauterine device (IUD), patches.

Frequency and timing of doses Once daily, at the same time each day (tablets).

Adult dosage range Progestogen-only contraceptive 30mcg daily. Postcoital contraceptive 1.5mg as a single dose as soon as possible, within 12 hours, but no later than after 72 hours. HRT and combined oral contraceptive Dosage varies according to preparation used.

Onset of effect Within 4 hours, but contraceptive protection may not be fully effective for 14 days, depending on day of cycle tablets are started.

Duration of action 24 hours. Some effects, not including contraception, may persist for up to 3 months after levonorgestrel is stopped.

Diet advice None.

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

Missed dose Progestogen-only contraceptive If a tablet is delayed by 2 hours or more, regard it as a missed dose. See What to do if you miss a pill. Postcoital contraceptive If vomiting occurs within 3 hours, take another tablet immediately. If problem persists speak to your doctor or pharmacist without delay. Combined oral contraceptive Depends on preparation used. 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 menopausal symptoms, consult your doctor before stopping the drug.

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

Menstrual irregularities (blood spotting between periods or absence of menstruation) are the most common side effects of levonorgestrel alone; discuss with your doctor if they occur. Lower abdominal pain is a rare adverse effect but it may indicate pregnancy so you should consult your doctor promptly if it occurs. Other side effects of levonorgestrel-containing drugs include swelling of the ankles and feet, weight gain, nausea, vomiting, and breast tenderness. Discuss with your doctor if these are severe or if you experience headaches or depression. Long-term use is associated with increased risk of certain disorders (see Prolonged use).

INTERACTIONS

General note The beneficial effects of many drugs may be affected by levonorgestrel. Many others may reduce contraceptive protection. Consult your doctor or pharmacist before taking other medications.

SPECIAL PRECAUTIONS

Be sure to tell your doctor if:

· You have a personal or family history of breast cancer.

· You have liver or kidney problems, heart failure, high blood pressure, diabetes, asthma, epilepsy, porphyria, or sickle cell anaemia.

· You have abnormal vaginal bleeding.

· You have ever had migraines, severe headaches, blood clots, or a stroke.

· You have a history of depression.

· You are taking other medicines.

Pregnancy Not prescribed. May cause abnormalities 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.

Surgery and general anaesthetics The drug should be stopped before surgery.

PROLONGED USE

In a COC, the drug increases the thrombosis and breast cancer risk but reduces the endometrial and ovarian cancer risk. In a POP, it carries a small increased risk of breast cancer. As part of HRT, it increases the risk of thrombosis and breast cancer. HRT is advised only for short-term use around the menopause.

Monitoring Blood pressure checks, physical examination, and mammograms may be performed.