Progestin implants

The progestin implant method utilizes the subcutaneous implantation of capsules containing etonogestrel. These capsules release one fifth... 

Commonly used methods of reversible contraception include oral and transdermal contraceptives, long-acting injectable estrogens and progestins, implantable progestins, condoms, spermicides, withdrawal, the diaphragm, periodic abstinence, and the intrauterine device. These methods differ in their relative effectiveness, safety, and patient acceptability." ... 

Progestin implants Pregnancy Passive contraception Requires outpatient surgical 0.3 0.3... 

As of 1994, there were approximately 47 progestin-containing contraceptive dmg formulations sold in the United States for use as oral contraceptives (Table 3). In addition, there are three nonoral contraceptive formulations containing progestins ie, one injectable (Depo-Provera), one as an intrauterine device (lUD) (Progestasert), and one implantable (Norplant). Of the oral formulations, all but two also contain an estrogen component, ethynylestradiol. 

Implanted Contraceptives. Controlled release of contraceptive progestins also can be accompHshed by incorporating the dmg into an implantable cylinder or rod. The best known implant is Norplant, developed by the Population Council. Norplant is composed of six matchlike silastic cylinders with the progestogen levonorgestrel (11) incorporated on the inside of each cylinder. After implantation under the skin, the product can provide effective contraception for a period of five years (43,44). Since silastic is not biodegradable, the implant can be removed from a patient at any time. 

Clinical studies also have been carried out with nonbio degradable implants releasing the progestin desogestrel (8). Unlike levonorgestrel, desogestrel possesses lower androgenic activity and thus has less adverse effect on blood Hpids. 

Progestin-only contraceptives (Fig. 4) contain low-doses of progestins (e.g. 350 pg norethindrone or 75 pg norgestrel) that have to be administered daily without interruption. The lowest expected failure rate during the first year of use is 0.5%, while the typical failure rate amounts to 3%. Subdermal implants of norgestrel (216 mg) for sustained release provides for long-term (for up to 5 years) contraceptive effects characterized by failure rates of only 0.05%. Reliable contraception for 3 months can be achieved by an intramuscular injection of a crystalline suspension of 150 mg medroxyprogesterone acetate (Fig. 3) (failure rate 0.3%). 

Impiant Contraceptive Systems (Progestins) levonorgestrel 6 capsules, each containing 36 mg levonorgestrel for subdermal implantation... 

IMPLANT CONTRACEPTIVE SYSTEM. Levonorgestrel, a progestin, is available as an implant contraceptive system (Norplant System). Six capsules, each containing levonorgestrel, are implanted under local anestiiesia in die subdermal (below the skin) tissues of the mid-portion of die upper arm. The capsules provide contraceptive protection for 5 years but may be removed at any time at die request of the patient. See Table 52-3 for more information on ways to promote an optimal response when taking die contraceptive hormones. 

Women who particularly benefit from progestin-only methods, including minipills, are those who are breast-feeding, those who are intolerant to estrogens, and those with concomitant medical conditions in which estrogen is not recommended. Also injectable and implantable contraceptives are beneficial for women with compliance issues. 

IUDs cause low-grade, intrauterine inflammation and increased prostaglandin formation. In addition, endometrial suppression is caused by the progestin-releasing IUD. They are spermicidal and also interfere with implantation of the fertilized ovum. Efficacy rates are greater than 99% with both perfect use and typical use. 

Progestins, of which progesterone is a prime example, induce endometrial maturation following ovulation, setting the stage for implantation of a fertilized ovum and pregnancy ... 

Progenote a very early form of life from which more complex living forms evolved. Progestin a steroid that is essential for the implantation of a fertilized egg. 

Studies indicate a significant trend toward higher rates of Ml and strokes with increasing doses of progestin in combination oral contraceptives. There have been postmarketing reports of Ml coincident with levonorgestrel implant system use. 

Small doses of progestins administered orally or by implantation under the skin can be used for contraception. They are particularly suited for use in patients for whom estrogen administration is undesirable. They are about as effective as intrauterine devices or combination pills containing 20-30 meg of ethinyl estradiol. There is a high incidence of abnormal bleeding. 

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