Implanon

How does it work?

Implanon is a long-acting progesterone-only contraceptive implant that contains the active ingredient etonogestrel. Etonogestrel is a synthetic form of the naturally occurring female sex hormone, progesterone. It prevents pregnancy in two ways.

In a woman's normal menstrual cycle, an egg matures and is released from the ovaries (ovulation). The ovary then produces progesterone, preventing the release of further eggs and priming the lining of the womb for a possible pregnancy. If pregnancy occurs, progesterone levels in the body remain high, maintaining the womb lining. If pregnancy does not occur, progesterone levels in the body fall, resulting in a menstrual period.

Etonogestrel tricks the body processes into thinking that ovulation has already occurred, by maintaining high levels of the synthetic progesterone. This prevents the release of eggs from the ovaries and is the main way in which etonogestrel prevents pregnancy.

Etonogestrel also affects the natural mucus at the neck of the womb (cervix). It increases the thickness of this mucus, making it more difficult for sperm to cross from the vagina into the womb. By preventing sperm entering the womb, successful fertilisation of an egg, leading to pregnancy, is less likely.

Implanon is a small plastic implant containing etonogestrel that is inserted under the skin of the upper arm. (The area will be numbed first using a local anaesthetic.) The plastic implant slowly releases etonogestrel into the bloodstream.

Implanon will prevent pregnancy from the time it is inserted. It will provide contraception for three years if left in place, but can be removed at any time by your doctor or family planning nurse, for example if you decide you want to have a baby, or if you have unacceptable side effects. The implant doesn't dissolve in the body and should not be left in place any longer than three years. After the implant is removed you are no longer protected against pregnancy and your normal menstrual cycle will rapidly return.

If you have not been using another hormonal contraceptive, the implant should be inserted between days one to five of your menstrual cycle (day one is the first day of your period). If you are changing from another hormonal contraceptive to Implanon, your doctor or family planning nurse will tell you when the implant needs to be inserted.

What is it used for?

Contraception in women aged 18 to 40 years.

Warning!

After your implant is inserted, your doctor should, together with you, feel for the actual presence of Implanon in your arm. In case of doubt you will have to use a condom until the doctor and you are absolutely sure that the implant has been inserted. In rare cases the doctor may have to use ultrasound or magnetic resonance imaging, or may have to take blood samples, to make sure that the implant is inside your arm.

It is recommended that you return to your doctor for a check-up three months after the implant is inserted. Your blood pressure should be checked at this appointment.

You may experience changes in your menstrual bleeding after this contraceptive is inserted. You may experience more frequent or longer heavier bleeding, or you may get spotting or no bleeding at all.

This contraceptive will not protect you or your partner from sexually transmitted diseases. Using a condom can provide this protection.

If you are due to have planned surgery you should consult your doctor about your implant beforehand. It may be recommended that your implant is removed before planned surgery and during long periods of immobility.

The implant should not be left in place for longer than three years.

In heavier women with a body mass index higher than 35 kg/m2, the contraceptive effect of this implant may not last for three years. If this applies to you, your doctor may need to replace your implant earlier than every three years for continued contraception.

On rare occasions, when it is time for the implant to be removed it may have moved slightly from the original insertion site and your doctor or family planning nurse may have difficulty locating it. If this is the case, minor surgery may be required to remove the implant.

It is important to be aware that all users of hormonal contraceptives appear to have a small increase in the risk of being diagnosed with breast cancer compared to non-users. However, it is important to weigh the risks against the known benefits of the contraceptive. Discuss this with your doctor.

Women who suffer from a condition called chloasma, which causes yellowish-brown patches of colouring on the skin, particularly the face, should avoid prolonged exposure to sunlight or ultraviolet radiation, eg sunbeds or UV lamps, while this implant is in place, as it can make this condition worse.

You should consult your doctor immediately if you experience any of the following while your implant is in place, as it may need to be removed: severe swelling or stabbing pains in either of your legs, breathlessness, pain on breathing or coughing, coughing up blood, chest pain, itching of the whole body, yellowing of the skin or eyes (jaundice), sudden severe abdominal pain, if you feel a lump in your breast, or if you become pregnant.

Use with caution in

History of breast cancer

History of blood clots in the blood vessels (thromboembolism), eg deep vein thrombosis or pulmonary embolism

High blood pressure

Decreased liver function

Diabetes

Women with a tendency to suffer from brown patches on the skin, particularly the face (chloasma) often due to pregnancy or oral contraceptives

Not to be used in

Women with an active blood clot in a vein, eg in the legs (deep vein thrombosis) or the lungs (pulmonary embolism)

Progestogen dependent cancer

Severe liver disease or history of severe liver disease if liver function has not returned to normal

Vaginal bleeding of unknown cause

Pregnancy

Hereditary blood disorders called porphyrias.

This medicine should not be used if you are allergic to one or any of its ingredients. Please inform your doctor or pharmacist if you have previously experienced such an allergy. If you feel you have experienced an allergic reaction, stop using this medicine and inform your doctor or pharmacist immediately.

Pregnancy and Breastfeeding

Certain medicines should not be used during pregnancy or breastfeeding. However, other medicines may be safely used in pregnancy or breastfeeding providing the benefits to the mother outweigh the risks to the unborn baby. Always inform your doctor if you are pregnant or planning a pregnancy, before using any medicine.

This medicine should not be used in women who are pregnant or think they could be pregnant. Seek medical advice from your doctor in the unlikely event that you fall pregnant while you have the implant in place, so that it can be removed.

Etonogestrel does not affect the amount or quality of breast milk produced, but may pass into breast milk in small amounts. The manufacturer states that it may be used by women who are breastfeeding, however development and growth of the child should be carefully followed. Seek medical advice from your doctor.

Side effects

Medicines and their possible side effects can affect individual people in different ways. The following are some of the side effects that are known to be associated with this medicine. Because a side effect is stated here, it does not mean that all people using this medicine will experience that or any side effect.

Headache

Acne

Weight gain

Breast tenderness or pain

Irregular menstrual bleeding

Vaginal infections

Depressed mood

Decreased sex drive

Decreased appetite

Nervousness

Dizziness

Hot flushes

Hair loss or growth

Disturbances of the gut, eg abdominal pain, nausea, vomiting, constipation, diarrhoea

Bruising at site of implant

Irritation, pain or itching at site of implant

Scarring or abscess at site of implant

Vaginal discharge

Migraine

Rise in blood pressure

Ovarian cysts

The side effects listed above may not include all of the side effects reported by the drug's manufacturer. For more information about any other possible risks associated with this medicine, please read the information provided with the medicine or consult your doctor or pharmacist.

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