Intrauterine devices

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. 

Intrauterine devices are medical products that prevent conception when placed in the utems. In spite of their ancient origins, modem intrauterine devices (lUDs) have been widely used only in the last 30 years. The two generic subclasses of lUDs are nonmedicated (inert) devices and medicated lUDs, ie, progestin-releasing and copper lUDs. 

After insertion of an lUD, polymorphonuclear leukocytes and macrophages accumulate in the uterine cavity. These cells appear to phagocytize sperm and Hberate a blastotoxic toxin (92,93). Intrauterine devices also may create a hostile environment, perhaps because antibodies are produced that interfere with implantation of the fertilized ovum (93). 

Intrauterine devices, Population Reports, Series B, no. 3, Population Information Program, The Johns Hopkius University, Baltimore, 1979. 

Oral, transdermal, and transvaginal contraceptives, as well as intrauterine devices and most barrier contraceptives, do not protect against sexually transmitted diseases. 

Menorrhagia also may be treated with the levonorgestrel-releasing intrauterine device (IUD). This is a very effective treatment that consistently reduces menstrual flow by 90% or greater.29,30 Its use has resulted in the postponement or cancellation of scheduled endometrial resection surgery or hysterectomy. Specifically, 60% of treated patients have been able to avoid hysterectomy.30,34,35... 

Ethylene vinyl acetate has also found major applications in drug delivery. These copolymers used in drug release normally contain 30-50 wt% of vinyl acetate. They have been commercialized by the Alza Corporation for the delivery of pilocarpine over a one-week period (Ocusert) and the delivery of progesterone for over one year in the form of an intrauterine device (Progestasert). Ethylene vinyl acetate has also been evaluated for the release of macromolecules such as proteins. The release of proteins form these polymers is by a porous diffusion and the pore structure can be used to control the rate of release (3). Similar nonbiodegradable polymers such as the polyurethanes, polyethylenes, polytetrafluoroethylene and poly(methyl methacrylate) have also been used to deliver a variety of different pharmaceutical agents usually as implants or removal devices. 

A more common contraceptive device is the intrauterine device (IUD). The first type of intrauterine device used was undedicated. These have received increased attention since the use of polyethylene plastics and silicone rubbers [194-196], These materials had the ability to resume their shape following distortion. Because they are unmedicated, these IUDs cannot be classifieds as sustained-release products. It is believed that their mechanism of action is due to local endometrial responses, both cellular and cytosecretory... 

Fig. 16 Schematic diagram of the Progestasert intrauterine device for the release of progesterone.

In human medicine, metallic copper is used in some intrauterine devices, and various copper compounds are used as emetics and to treat rheumatoid arthritis (USEPA 1980 Aaseth and Norseth 1986). Some individuals wear copper bracelets as treatment for arthritis although its therapeutic value has little support (USEPA 1980). 

UD, intrauterine device NSAID, nonsteroidal antiinflammatory drug OC, oral contraceptive,... 

Phenobarbital, carbamazepine, and phenytoin potentially reduce efficacy of OCs, and many anticonvulsants are known teratogens. The use of condoms in conjunction with high-estrogen OCs or intrauterine devices (IUDs) may be considered for women taking these drugs. 

Many technicians may not be famihar with terms such as sublingual (under the tongue), buccal (between the cheek and gingiva), otic, and so on. A clear description of each of these nontraditional routes (i.e., other than gavage routes) should be discussed with technicians, and instructions may also be written down and given to them. Demonstrations are often useftd to illustrate selected techniques of administration (e.g., to use an inhaler or nebulizer). Some chemicals must be placed by technicians into body orifices (e.g., medicated intrauterine devices such as Proges-terset). 

Rule 14 deals with devices used for contraception or the prevention of transmission of sexually transmitted diseases - Class 11b, for example, condoms, contraceptive diaphragms and if they are implantable or long-term invasive Class 111, for example, intrauterine devices. 

Effective forms of contraception include both primary and secondary forms of contraception. Primary forms of contraception include Tubal ligation, partner s vasectomy, intrauterine devices, birth control pills, and... 

Only one implantable contraceptive preparation is available at present in the USA. Etonogestrel, also used in some oral contraceptives, is available in the subcutaneous implant form listed in Table 40-3. Several hormonal contraceptives are available as vaginal rings or intrauterine devices. Intramuscular injection of large doses of medroxyprogesterone also provides contraception of long duration. 

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. 

The wearing of copper bracelets to benefit arthritis is an apocryphal use of copper. It is not clear whether any measurable amount of copper is dissolved by the body. The average weight loss from copper bracelets is 12 mg month-1 while they are worn. Studies show that components in human sweat could solubilize this metal and possibly aid its absorption. On the other hand, copper-coated intrauterine devices can lead to the dissolution of about 25-50 mg Cu per year. There are no studies to show whether this leads to chronic copper toxicity or whether there is a protective effect against... 

Similarly, a massive Finnish mortality study, covering 1 585 000 women-years of oral contraceptive use and two million women-years of copper-bearing intrauterine device use, showed no increase in relative risk among oral contraceptive users for myocardial infarction or cerebral hemorrhage deaths however, there might have been an increased risk of death from pulmonary embolism among users of oral contraceptives (43). 

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