RESUMO
Several progestin-only long acting contraceptives are currently available in the form of implants or injectables. Vaginal rings are another contraceptive option in the final stages of development. These steroid-containing polymer rings are placed in the vagina, providing relatively constant drug release, thus allowing for lower effective doses. Vaginal rings have the advantage of being user-controlled and non-provider dependent, and their use is non-coital related. The first clinical study with medroxyprogesterone acetate vaginal rings was published in 1970. Since then numerous clinical trials testing different steroids and doses have followed. A large Phase III multicenter clinical trial with a levonorgestrel ring, releasing 20 microg/day, was coordinated and sponsored by WHO. The cumulative one-year pregnancy rate was 4. 5%. The principal reasons for discontinuation were menstrual disturbances (17.2%), followed by frequent expulsion of the ring (7. 1%), and vaginal symptoms (6.0%). The finding of erythematous lesions in the vagina in some women has led to the development of a more flexible device. Collaboration with industry should facilitate the manufacture of a redesigned levonorgestrel ring with a higher release rate. The Population Council is also developing a vaginal ring containing Nestorone for 6 months of continuous use. Ovulation inhibition was achieved in over 97% of the segments studied, with rings releasing either 50, 75, or 100 microg/day. No pregnancies occurred in women using the low-dose ring, while one pregnancy each occurred in the intermediate- and high-dose ring groups for a 6-month cumulative pregnancy rate of 0.0, 1.9, and 2.1%. Bleeding irregularities were common. Nestorone is orally inactive; therefore this ring is also excellent for use in lactating women.
Assuntos
Anticoncepcionais Femininos/administração & dosagem , Progestinas/administração & dosagem , Administração Intravaginal , Anticoncepcionais Femininos/sangue , Anticoncepcionais Femininos/normas , Preparações de Ação Retardada/farmacocinética , Preparações de Ação Retardada/normas , Implantes de Medicamento/farmacocinética , Implantes de Medicamento/normas , Feminino , Humanos , Gravidez , Progestinas/sangue , Progestinas/normasRESUMO
Progestin implants for contraception are highly effective, safe, and the most convenient choice for many women. Progestin implants currently on the market, preparing for launch, or under investigation are reviewed here. Their basic galenic and pharmacokinetic features, as well as their contraceptive effectiveness, are described. The first progestin-only contraceptive implant placed on the market was Norplant, a multiunit system. Since then, several single- and double-rod implants have been developed, each using one of four different progestins: levonorgestrel, etonogestrel, Nestorone and nomegestrol acetate. Jadelle is similar to Norplant but consists of only two, rather than six, Silastic rods to simplify insertion and removal; nevertheless, levonorgesterel serum levels are identical, and performance is the same for both systems. The single implant systems reviewed here are: Implanon with a 3-year duration; Nestorone implants for breast feeding and non-breast feeding women lasting up to 2 years; and Uniplant, which is effective for 1 year. The advantages and disadvantages of progestin implants, the importance of counseling for increasing user satisfaction, and the future outlook for this contraceptive method are also discussed.
Assuntos
Progestinas/normas , Administração Intravaginal , Anticoncepcionais Femininos/administração & dosagem , Anticoncepcionais Femininos/farmacocinética , Anticoncepcionais Femininos/normas , Preparações de Ação Retardada/farmacocinética , Preparações de Ação Retardada/normas , Implantes de Medicamento/farmacocinética , Implantes de Medicamento/normas , Feminino , Humanos , Gravidez , Progestinas/administração & dosagem , Progestinas/farmacocinéticaRESUMO
Contraceptive methods for breastfeeding women should be safe for the mother and infant and should not interfere with lactation. Progestin-only methods meet these conditions and can be used from the sixth week postpartum. Because all progestins are excreted in milk, those that are insufficiently active by the oral route are preferable to avoid any possible effect on the baby. These steroids, however, must be administered to the mother by a non-oral route. Initially, progesterone was administered subdermally to test this concept. Subsequently, a progesterone vaginal ring was developed to be used continuously for 3 to 4 months and replaced with a new device, as needed, until weaning. Clinical trials have shown a high contraceptive efficacy (over 98.5%) and safety. The gross continuation rate of this method is approximately 40% at 12 months of use, with use-related problems being the main reason for discontinuation (26.8%). Currently, a Nestorone vaginal ring is under development, delivering 50 microg of Nestorone per day. It may be used continuously for up to one year, even if weaning occurs earlier. Both of these progestin-only rings prolong lactational amenorrhea to 10 to 12 months, which represents a health benefit and convenience for many women. The registration of the progesterone vaginal ring, developed as a contraceptive method to be used exclusively during lactation, has been approved in Chile and Perú. The fact that it is a user-controlled long-term contraceptive that delivers a natural hormone makes it an attractive option for many women.
Assuntos
Lactação/efeitos dos fármacos , Norprogesteronas/administração & dosagem , Administração Intravaginal , Adulto , Amenorreia/etiologia , Aleitamento Materno , Anticoncepcionais Femininos/administração & dosagem , Anticoncepcionais Femininos/efeitos adversos , Anticoncepcionais Femininos/normas , Preparações de Ação Retardada , Avaliação de Medicamentos , Implantes de Medicamento/efeitos adversos , Implantes de Medicamento/normas , Feminino , Seguimentos , Humanos , Lactente , Recém-Nascido , Masculino , Ciclo Menstrual/efeitos dos fármacos , Norprogesteronas/efeitos adversos , Norprogesteronas/normas , Projetos Piloto , Gravidez , Taxa de GravidezRESUMO
Objetivo: Conocer si los efectos secundarios de los implantes anticonceptivos subdérmicos a base de Levanorgestel: Norplant son motivo de retiro. Material y Métodos: Comprende 7.776 implantes colocados entre abril/30/86 a agosto 31/93(88 meses). Se realizaron 1859 retiros por motivos descritos por las usuarias (23.90 por ciento). El estudio Institucional se agrupó en cinco categorías. Resultados: I. Motivo esperado de retiro: 681 pac. (36.63 por ciento); a) Deseo de embarazo:378 pac.(55.50 por ciento); b)Cumplieron los cinco años de uso: 257 pac.(37.73 por ciento); c) Cambio de Método: 46 pac. (6.75 por ciento). II. retiro de Norplant por un motivo(médicos o extramédicos) 958 pac. (51.53 por ciento). III. Retiro de Norplant por dos motivos: 192 pac. (10.32 por ciento).IV.Retiro por tres motivos: 24 pac.(1.29 por ciento).V_. Retiro pos cuatro motivos. 4 pac.(0.21 por ciento). Hallazgo Sobresaliente: II. Mótivo único: 958 pac. (51.61 por ciento): Disfunciones mestruales: 329 pac. (34.34 por ciento); Médicos Generales, 198 pac. (20.66 por ciento); especialidades médicas: 125 pac. (13.02 por ciento); cefalea: 117 pac. (12.21 por ciento); motivos personales; 101 pac.(10.54 por ciento); várices: 55 pac. (5.74 por ciento); embarazo: 33 pac. (3.44 popr ciento). Conclusión: Efectos secundarios:relativos. Prima un motivo de retiro. Continuidad de uso de 76.10 por ciento