"May 23, 2012 -- Women using birth control pills may have a 20 times greater risk of an unplanned pregnancy than women using longer-acting forms of birth control like an intrauterine device (IUD) or implant, new research shows.
IMPLANON (etonogestrel implant) is a progestin-only, soft, flexible implant preloaded in a sterile, disposable applicator for subdermal use. The implant is off-white, non-biodegradable and 4 cm in length with a diameter of 2 mm (see Figure 22). Each implant consists of an ethylene vinylacetate (EVA) copolymer core, containing 68 mg of the synthetic progestin etonogestrel, surrounded by an EVA copolymer skin. Once inserted subdermally, the release rate is 60 to 70 mcg/day in Week 5 to 6 and decreases to approximately 35 to 45 mcg/day at the end of the first year, to approximately 30 to 40 mcg/day at the end of the second year, and then to approximately 25 to 30 mcg/day at the end of the third year. IMPLANON is a progestin-only contraceptive and does not contain estrogen. IMPLANON does not contain latex and is not radio-opaque.
Figure 22 (Not to scale)
Etonogestrel [13-Ethyl-17-hydroxy-11-methylene-18,19-dinor-17α-pregn-4-en-20-yn-3-one], structurally derived from 19-nortestosterone, is the synthetic biologically active metabolite of the synthetic progestin desogestrel. It has a molecular weight of 324.46 and the following structural formula (Figure 23).
What are the possible side effects of etonogestrel implant (Implanon, Nexplanon)?
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat.
Call your doctor at once if you have any of these serious side effects:
- warmth, redness, swelling, or oozing where the implant was inserted;
- sudden numbness or weakness, especially on one side of the body;
- severe pain or cramping in your pelvic area (may be only on one side);
- sudden severe headache, confusion, pain behind the eyes, problems with vision, speech, or...
What are the precautions when taking etonogestrel implant (Implanon)?
Before using etonogestrel, tell your doctor or pharmacist if you are allergic to it; or to other progestins (such as norethindrone, desogestrel); or to any anesthetics or antiseptics that might be used in the procedure; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.
Before using this medication, tell your doctor or pharmacist your medical history, especially of: blood clots (for example in the legs, eyes, lungs), blood clotting disorders (such as protein C or protein S deficiency), high blood pressure, abnormal breast exam, personal or family history of cancer (especially breast or cervical cancer), high cholesterol or triglyceride (blood fat)...
Last reviewed on RxList: 9/6/2016
This monograph has been modified to include the generic and brand name in many instances.
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