Levonorgestrel
Brand names Microval, Norgeston
Used in the following combined preparations Cyclo-progynova, Eugynon 30, Microgynon 30, Ovranette, and others
General Information
Levonorgestrel is a synthetic hormone similar to progesterone, a natural female sex hormone. The drug’s primary use is as an ingredient 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 both in combined oral contraceptives with an oestrogen drug and in progestogen-only preparations.
Levonorgestrel is occasionally given with an oestrogen for emergency, postcoital contraception. It is also given in combination with an oestrogen drug in hormone replacement therapy to treat menopausal symptoms.
Levonorgestrel rarely causes serious adverse effects. When it is used without an oestrogen, menstrual irregularities, especially mid-cycle, or “breakthrough”, bleeding are common.
INFORMATION FOR USERS
Your drug prescription is tailored for you. Do not alter dosage without checking with your doctor.
How taken
Tablets, implant, intrauterine device (IUD).
Frequency and timing of doses
Once daily, at the same time each day.
Adult dosage range
Progestogen-only pills 30mcg daily.
Onset of effect
Levonorgestrel starts to act within 4 hours, but contraceptive protection may not be fully effective for 14 days, depending on which day of the cycle the tablets are started.
Duration of action
24 hours. Some effects may persist for up to 3 months after levonorgestrel is stopped.
Diet advice
None.
Storage
Keep in a closed container in a cool, dry place out of the reach of children.
Missed dose
If a tablet is delayed by 3 hours or more, regard it as a missed dose. 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 menstrual periods or absence of
menstruation) are the most common side effects of levonorgestrel alone.
Quick Reference
Drug group Female sex hormone and oral contraceptive
Overdose danger rating Low
Dependence rating Low
Prescription needed Yes
Available as generic No
Special Precautions
Be sure to tell your doctor if:
You have a long-term liver problem. You have heart failure or high blood
pressure. You have diabetes.
You have had blood clots or a stroke.
You are taking other medications.
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.
prolonged use
Problems are rare.
Interactions
General note
The beneficial effects of many drugs, including bromocriptine, oral anticoagulants, anticonvulsants, and antihypertensive and antidiabetic drugs, may be affected by levonorgestrel. Many other drugs may affect the action of oral
contraceptives, reducing contraceptive protection. These include anticonvulsants, antituberculous drugs, and antibiotics. Inform your doctor that you are taking this drug before taking additional prescribed medication.
