Insertion and Removal of Implanon

CHAPTER 147 Insertion and Removal of Implanon



Stephen A. Grochmal, Dale A. Patterson


Implanon is an implantable contraceptive device that functions like other progestin-based contraceptives by developing a thick, hostile cervical mucus and eventual atrophy of the uterine endometrium. Compared to the original Norplant System, Implanon appears to cause a greater inhibition of ovulation in patients. Implanon is designed as a single implant measuring 4 cm long with a diameter of 2 mm and an outer structural membrane composed of ethylene vinyl acetate (EVA) copolymer (Fig. 147-1). This copolymer outer membrane may not react with the surrounding tissue as much as Norplant did, leading to less tissue fibrosis; thus permitting easier extraction when its content is exhausted. The implant core contains 68 mg of etonogestrel in EVA. The progestin is released initially at the rate of 60 µg/day in weeks 5 to 6 of use and then decreases to 35 to 45 µg/day at the end of the first year. The released amount of etonogestrel continues to decrease to 30 to 40 µg/day and 25 to 30 µg/day at 2 and 3 years of use, respectively. Implanon is effective for 3 years and has a shelf life of 5 years. The implant is placed in the subcutaneous tissue of the upper arm with a 19-gauge disposable, preloaded inserter. The insertion is a minor surgical procedure performed in the office. Implanon was approved in July 2006 by the U.S. Food and Drug Administration (FDA).


image

Figure 147-1 Implanon device.


(Courtesy of Schering-Plough Corp., Kenilworth, NJ.)



Indications


Implanon is used for contraception.



Contraindications



Absolute


Pregnancy is an absolute contraindication.



Relative



• Thromboembolism

• Breast cancer

• Hepatic disorders

• Unexplained abnormal vaginal bleeding

• Hypersensitivity to the components of the product

A detailed discussion of relative risks is available in the complete prescribing information at: www.implanon-usa.com/hcp.



Equipment



• Examination table

• Sterile surgical drapes and gloves, antiseptic solution, sterile skin marker

• Local anesthetic (1% lidocaine without epinephrine), syringes (3 mL), and needles (25 to image)

• Sterile gauze, adhesive bandage (self-adhesive wrap like Coban), pressure bandage

• Implanon product kit (Fig. 147-2) (no. 11 blade, straight and curved mosquito clamps, and forceps are needed for removal)

image

Figure 147-2 Implanon kit (see text for details).


(Courtesy of Schering-Plough Corp., Kenilworth, NJ.)



Precautions


Although progestin-containing contraceptives have not been shown to cause birth defects, it is imperative to ensure that a patient is not pregnant prior to inserting Implanon. If a patient is found to be pregnant or becomes pregnant after insertion, the device should be removed.


Caution is also advised in patients with bleeding disorders and patients taking anticoagulants. Implanon may be an appropriate contraceptive for these patients, but precautions should be taken to minimize bleeding.



Preprocedure Patient Education


Implanon is more than 99% effective, and when the device is inserted correctly risk of pregnancy is less than 1 per 100 women who use it. Approximately 82% of women continue to use Implanon for 2 or more years. Implanon may be less effective in women who are overweight or are taking certain types of medications. Contraception with progestins is very useful in patients with known hepatic disease, hypertension, psychosis, mental retardation, or a history of thromboembolism. It should be noted that the manufacturer lists thromboembolism, hepatic disorders, and breast cancer as contraindications to the use of Implanon but that clinical practice has shown that progestin-based contraceptives are safe in these patients and preferred over estrogen-containing products.


The implant must be removed after all the progestin is released, generally by the end of the third year. Women should be informed that Implanon does not protect against human immunodeficiency virus (HIV) or other sexually transmitted diseases. A detailed patient consent form is available from the manufacturer’s website and online at www.expertconsult.com.



Advantages



• Menstrual: Menstrual and ovulatory discomfort and cramping are decreased. There is less bleeding as compared to other implant devices, with more consistent amenorrhea reported (20% at 1 year). In Implanon users, uterine pain was reduced or eliminated in 88% of women previously experiencing dysmenorrhea.

• Sexual and psychological: Sexual intercourse may be more pleasurable because fear of pregnancy is reduced, allowing for more spontaneity.

• Risk of cancer: None known.

• Additional factors: There was a high continuation rate reported in the clinical trials, and asymptomatic follicular cysts were less common than with users of Mirena or Norplant. The single implant permits quick removal.


Disadvantages



• Menstrual: Amenorrhea and oligomenorrhea are commonly reported. A more common patient complaint is persistent irregular and less predictable menstrual bleeding.

• Sexual and psychological: The irregular bleeding may become disconcerting and possibly discourage sexual intercourse.

• Headache and acne are commonly reported side effects.

• Interactions with other medications may make Implanon less effective. These medications include barbiturates, griseofulvin, rifampin, phenylbutazone, carbamazepine, felbamate, oxcarbazepine, topiramate, and modafinil. Herbal remedies such as St. John’s wort may also reduce effectiveness. In these situations, a secondary nonhormonal method of birth control should be considered.


Patient Selection


The Implanon implant is particularly useful for women with contraindications to or severe side effects from estrogen. As previously mentioned, Implanon candidates would include those patients with a personal history of thrombosis, coronary artery disease, cerebrovascular disease, hypertension, or hepatic disorders. Included in this list are those patients who suffer from other related estrogen side effects including migraine headaches, previous history of drug-induced chloasma, and hypertriglyceridemia, and those women who are recently postpartum, breastfeeding, over the age of 35 years, or smokers. The published prescribing precautions are the same as for other progestin-only pills. Patients concerned about their fertility after discontinuation of Implanon should be counseled that they will experience a rapid return to baseline fertility, with over 94% of patients demonstrating ovulation within 3 to 6 weeks after removal of the implant. It is important to inform patients that irregular bleeding may be expected and might persist while the implant rod is in place. If the pattern of bleeding becomes intolerable, additional treatments can be employed to make the bleeding pattern more acceptable.

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May 14, 2017 | Posted by in GENERAL & FAMILY MEDICINE | Comments Off on Insertion and Removal of Implanon

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