Indications
Etonogestrel is a progestogen hormone used for long-acting, reversible contraception (birth control) in women. In this form it is a small, flexible rod (implant) placed just under the skin of the inner upper arm, where it slowly releases hormone and prevents pregnancy for up to 3 years. Etonogestrel is also used in a combined vaginal ring, but this write-up describes the implant.
How It Works
Etonogestrel is similar to the natural hormone progesterone. Released steadily into the blood, it mainly stops the ovaries from releasing an egg each month (ovulation). It also thickens the mucus at the neck of the womb so sperm cannot pass easily, and thins the womb lining. Once the implant is removed, the effect wears off quickly and fertility usually returns within weeks.
Dosage and Administration
One implant is inserted under the skin of the inner upper arm by a doctor or trained health worker, using local anaesthetic. The timing (for example during the first days of a period, or after childbirth or abortion) is decided by the health worker, who will tell you whether extra contraception is needed for the first 7 days.
- The implant works for up to 3 years and must be removed or replaced by the end of that time, or earlier if advised. Women with higher body weight may be advised to replace it sooner.
- It can be removed at any time by a trained health worker.
- You should be able to feel the rod under the skin; check it from time to time.
Interactions
Some medicines speed up the breakdown of Etonogestrel and can make the implant less effective, including Rifampicin, Rifabutin, Carbamazepine, Phenytoin, Phenobarbital, Primidone, Topiramate, Oxcarbazepine, Efavirenz and some other HIV medicines, Griseofulvin and the herbal remedy St John’s Wort. If you take any of these, use condoms as well during treatment and for 28 days after, or ask about another method. Etonogestrel may raise levels of Ciclosporin. Always tell your doctor you have an implant.
Contraindications
- Known or suspected pregnancy.
- Current blood clot in a vein (deep vein thrombosis or pulmonary embolism).
- Severe liver disease or liver tumour.
- Current or past breast cancer, or other cancers sensitive to sex hormones.
- Unexplained vaginal bleeding.
- Allergy to Etonogestrel or any part of the implant.
Side Effects
The most common change is in the bleeding pattern: periods may become irregular, more or less frequent, longer, lighter or may stop altogether. Other possible effects include headache, weight gain, acne, breast tenderness, mood changes, lower sex drive, stomach pain, dizziness and ovarian cysts. Pain, bruising or itching may occur where the implant was inserted. Rarely, the implant moves from its place or is hard to remove.
Get urgent medical help if you have pain or swelling in one leg, chest pain or sudden breathlessness (possible blood clot), severe pain in the lower stomach (possible ectopic pregnancy), yellowing of the skin or eyes, signs of a severe allergic reaction, or redness, pus or fever around the implant site. See your health worker if you cannot feel the implant or find a lump in your breast.
Pregnancy and Lactation
The implant must not be used during pregnancy; if you become pregnant, see your doctor so it can be removed. It can be used while breastfeeding: a small amount of hormone passes into breast milk but has not been shown to harm the baby or milk supply. Your health worker will advise when to insert it after childbirth.
Precautions and Warnings
- The implant does not protect against HIV or other sexually transmitted infections; use condoms for that.
- If pregnancy happens with the implant, there is a higher chance it is outside the womb (ectopic).
- Tell your doctor if you have diabetes, high blood pressure, depression, past blood clots or liver problems.
- Insertion and removal must be done only by trained health workers.
Overdose
The implant releases a fixed small amount of hormone, so overdose is unlikely. If more than one implant has been inserted by mistake, the extra one should be removed by a trained health worker.
Therapeutic Class
Hormonal contraceptive; progestogen-only implant.
Storage
Store as directed on the pack, usually below 30°C in the original package, away from light and moisture and out of the reach of children. It is normally kept by the clinic until insertion.
Prepared by the Oshud Alo team from standard drug references. For information only; always follow your doctor's advice.