RESUMEN
Abstract Background: Levonorgestrel (LNG) is a progesterone receptor agonist used in both regular and emergency hormonal contraception; however, its effects on the endometrium as a contraceptive remain widely unknown and under public debate. Objective: To analyze the effects of LNG or mifepristone (MFP), a progesterone receptor antagonist and also known as RU-486, administered at the time of follicle rupture (FR) on endometrial transcriptome during the receptive period of the menstrual cycle. Methods: Ten volunteers ovulatory women were studied during two menstrual cycles, a control cycle and a consecutively treated cycle; in this last case, women were randomly allocated to two groups of 5 women each, receiving one dose of LNG (1.5 mg) or MFP (50 mg) the day of the FR by ultrasound. Endometrial biopsies were taken 6 days after drug administration and prepared for microarray analysis. Results: Genomic functional analysis in the LNG-treated group showed as activated the bio-functions embryo implantation and decidualization, while these bio-functions in the T-MFP group were predicted as inhibited. Conclusions: The administration of LNG as a hormonal emergency contraceptive resulted in an endometrial gene expression profile associated with receptivity. These results agree on the concept that LNG does not affect endometrial receptivity and/or embryo implantation when used as an emergency contraceptive.
Asunto(s)
Humanos , Femenino , Adulto , Adulto Joven , Implantación del Embrión/efectos de los fármacos , Mifepristona/farmacología , Levonorgestrel/farmacología , Anticonceptivos Hormonales Poscoito/farmacología , Endometrio , Transcriptoma/efectos de los fármacos , Ovulación , Factores de Tiempo , Mifepristona/administración & dosificación , Levonorgestrel/administración & dosificación , Anticonceptivos Hormonales Poscoito/administración & dosificaciónRESUMEN
BACKGROUND: Levonorgestrel (LNG) is a progesterone receptor agonist used in both regular and emergency hormonal contraception; however, its effects on the endometrium as a contraceptive remain widely unknown and under public debate. OBJECTIVE: To analyze the effects of LNG or mifepristone (MFP), a progesterone receptor antagonist and also known as RU-486, administered at the time of follicle rupture (FR) on endometrial transcriptome during the receptive period of the menstrual cycle. METHODS: Ten volunteers ovulatory women were studied during two menstrual cycles, a control cycle and a consecutively treated cycle; in this last case, women were randomly allocated to two groups of 5 women each, receiving one dose of LNG (1.5 mg) or MFP (50 mg) the day of the FR by ultrasound. Endometrial biopsies were taken 6 days after drug administration and prepared for microarray analysis. RESULTS: Genomic functional analysis in the LNG-treated group showed as activated the bio-functions embryo implantation and decidualization, while these bio-functions in the T-MFP group were predicted as inhibited. CONCLUSIONS: The administration of LNG as a hormonal emergency contraceptive resulted in an endometrial gene expression profile associated with receptivity. These results agree on the concept that LNG does not affect endometrial receptivity and/or embryo implantation when used as an emergency contraceptive.
Asunto(s)
Anticonceptivos Hormonales Poscoito/farmacología , Implantación del Embrión/efectos de los fármacos , Endometrio , Levonorgestrel/farmacología , Mifepristona/farmacología , Transcriptoma/efectos de los fármacos , Adulto , Anticonceptivos Hormonales Poscoito/administración & dosificación , Femenino , Humanos , Levonorgestrel/administración & dosificación , Mifepristona/administración & dosificación , Ovulación , Factores de Tiempo , Adulto JovenRESUMEN
BACKGROUND: The days just prior to ovulation are the most crucial for emergency contraception (EC) efficacy. Ulipristal acetate (UPA) and levonorgestrel's (LNG) capacity to inhibit follicular rupture have never been compared directly at this time of the cycle. STUDY DESIGN: Raw data from three pharmacodynamics studies with similar methodology were pooled to allow direct comparison of UPA, LNG and LNG + meloxicam's ability to prevent ovulation when administered orally in the advanced follicular phase, with a leading follicle of ≥ 18 mm. RESULTS: Forty eight LNG-treated (1.5 mg) cycles, 31 LNG (1.5 mg) + meloxicam (15 mg), 34 UPA (30 mg) cycles and 50 placebo cycles were compared. Follicle rupture was delayed for at least 5 days in 14.6%, 38.7%, 58.8% and 4% of the LNG-, LNG + meloxicam-, UPA- and placebo-treated cycles, respectively. UPA was more effective than LNG and placebo in inhibiting follicular rupture (p = .0001), while LNG, when administered at this time of the cycle, was not different than placebo. The addition of meloxicam improved the efficacy of LNG in preventing follicular rupture (p = .0292 vs. LNG; p = .0001 vs. placebo; non-significant vs. UPA). UPA was effective in preventing rupture in the 5 days following treatment, even when administered at the time of the luteinizing hormone (LH) surge (UPA 79%, LNG 14% and placebo 10%). None of the treatments were effective when administered on the day of the LH peak. The median time from treatment to rupture was 6 days during the ulipristal cycles and 2 days in the placebo and LNG/LNG + meloxicam cycles (p = .0015). CONCLUSION: Although no EC treatment is 100% effective in inhibiting follicular rupture when administered in the late follicular phase, UPA is the most effective treatment, delaying ovulation for at least 5 days in 59% of the cycles. LNG is not different from placebo in inhibiting follicular rupture at this advanced phase of the cycle. No treatment was effective in postponing rupture when administered on the day of LH peak.
Asunto(s)
Anticonceptivos Hormonales Poscoito/farmacología , Anticonceptivos Sintéticos Poscoito/farmacología , Levonorgestrel/farmacología , Norpregnadienos/farmacología , Folículo Ovárico/efectos de los fármacos , Ovulación/efectos de los fármacos , Adolescente , Adulto , Chile , Estudios Cruzados , Inhibidores de la Ciclooxigenasa/farmacología , República Dominicana , Método Doble Ciego , Combinación de Medicamentos , Femenino , Humanos , Estimación de Kaplan-Meier , Luteinización/efectos de los fármacos , Hormona Luteinizante/sangre , Meloxicam , Tiazinas/farmacología , Tiazoles/farmacología , Adulto JovenRESUMEN
BACKGROUND: Emergency contraception can prevent unintended pregnancies, but current methods are only effective if used as soon as possible after sexual intercourse and before ovulation. We compared the efficacy and safety of ulipristal acetate with levonorgestrel for emergency contraception. METHODS: Women with regular menstrual cycles who presented to a participating family planning clinic requesting emergency contraception within 5 days of unprotected sexual intercourse were eligible for enrolment in this randomised, multicentre, non-inferiority trial. 2221 women were randomly assigned to receive a single, supervised dose of 30 mg ulipristal acetate (n=1104) or 1.5 mg levonorgestrel (n=1117) orally. Allocation was by block randomisation stratified by centre and time from unprotected sexual intercourse to treatment, with allocation concealment by identical opaque boxes labelled with a unique treatment number. Participants were masked to treatment assignment whereas investigators were not. Follow-up was done 5-7 days after expected onset of next menses. The primary endpoint was pregnancy rate in women who received emergency contraception within 72 h of unprotected sexual intercourse, with a non-inferiority margin of 1% point difference between groups (limit of 1.6 for odds ratio). Analysis was done on the efficacy-evaluable population, which excluded women lost to follow-up, those aged over 35 years, women with unknown follow-up pregnancy status, and those who had re-enrolled in the study. Additionally, we undertook a meta-analysis of our trial and an earlier study to assess the efficacy of ulipristal acetate compared with levonorgestrel. This trial is registered with ClinicalTrials.gov, number NCT00551616. FINDINGS: In the efficacy-evaluable population, 1696 women received emergency contraception within 72 h of sexual intercourse (ulipristal acetate, n=844; levonorgestrel, n=852). There were 15 pregnancies in the ulipristal acetate group (1.8%, 95% CI 1.0-3.0) and 22 in the levonorgestrel group (2.6%, 1.7-3.9; odds ratio [OR] 0.68, 95% CI 0.35-1.31). In 203 women who received emergency contraception between 72 h and 120 h after sexual intercourse, there were three pregnancies, all of which were in the levonorgestrel group. The most frequent adverse event was headache (ulipristal acetate, 213 events [19.3%] in 1104 women; levonorgestrel, 211 events [18.9%] in 1117 women). Two serious adverse events were judged possibly related to use of emergency contraception; a case of dizziness in the ulipristal acetate group and a molar pregnancy in the levonorgestrel group. In the meta-analysis (0-72 h), there were 22 (1.4%) pregnancies in 1617 women in the ulipristal acetate group and 35 (2.2%) in 1625 women in the levonorgestrel group (OR 0.58, 0.33-0.99; p=0.046). INTERPRETATION: Ulipristal acetate provides women and health-care providers with an effective alternative for emergency contraception that can be used up to 5 days after unprotected sexual intercourse. FUNDING: HRA Pharma.
Asunto(s)
Anticonceptivos Sintéticos Orales/uso terapéutico , Anticonceptivos Hormonales Poscoito/uso terapéutico , Levonorgestrel/uso terapéutico , Norpregnadienos/uso terapéutico , Adulto , Coito , Anticoncepción Postcoital/métodos , Anticonceptivos Sintéticos Orales/administración & dosificación , Anticonceptivos Sintéticos Orales/efectos adversos , Anticonceptivos Sintéticos Orales/farmacología , Anticonceptivos Hormonales Poscoito/administración & dosificación , Anticonceptivos Hormonales Poscoito/efectos adversos , Anticonceptivos Hormonales Poscoito/farmacología , Femenino , Estudios de Seguimiento , Humanos , Levonorgestrel/administración & dosificación , Levonorgestrel/efectos adversos , Levonorgestrel/farmacología , Ciclo Menstrual/efectos de los fármacos , Metaanálisis como Asunto , Persona de Mediana Edad , Norpregnadienos/administración & dosificación , Norpregnadienos/efectos adversos , Norpregnadienos/farmacología , Ovulación/efectos de los fármacos , Embarazo , Resultado del TratamientoRESUMEN
Unintended and teenage pregnancies are major public health concerns in the United States. Emergency contraception is used to prevent pregnancy after failure of a contraceptive method or after unprotected intercourse. Expanded use of emergency contraception has the potential to reduce unintended pregnancy and induced abortions, while reducing state and federal healthcare expenditures. The recent approval of Plan B as an over-the-counter medication for individuals over 18 years of age should improve access to this medication. However, there are still widespread misconceptions about the mechanisms and implications of emergency contraception. Expanded access to emergency contraception is associated with increased use, but not associated with decreased efficacy, increased sexual risk-taking behavior, or less consistent use of traditional birth control methods. This review is designed to provide clinicians with information regarding the use of emergency contraception for reproductive age patients. It includes a brief description of methods of use, mechanisms of action, and side effect profiles of the most commonly used methods of emergency contraception, levonorgestrel and the Yuzpe method.
Asunto(s)
Anticoncepción Postcoital , Anticonceptivos Femeninos/administración & dosificación , Anticonceptivos Sintéticos Orales/administración & dosificación , Anticonceptivos Hormonales Poscoito , Levonorgestrel/administración & dosificación , Embarazo en Adolescencia , Embarazo no Deseado , Aborto Inducido , Adolescente , Adulto , Ensayos Clínicos como Asunto , Conducta Anticonceptiva , Anticoncepción Postcoital/economía , Anticoncepción Postcoital/métodos , Anticonceptivos Femeninos/efectos adversos , Anticonceptivos Sintéticos Orales/efectos adversos , Anticonceptivos Hormonales Poscoito/administración & dosificación , Anticonceptivos Hormonales Poscoito/efectos adversos , Anticonceptivos Hormonales Poscoito/economía , Anticonceptivos Hormonales Poscoito/farmacología , Femenino , Costos de la Atención en Salud , Humanos , Levonorgestrel/efectos adversos , Medicamentos sin Prescripción , Embarazo , Asunción de Riesgos , Conducta Sexual , Factores de Tiempo , Estados Unidos , United States Food and Drug Administration , Organización Mundial de la SaludRESUMEN
For emergency contraceptive, the rapid delivery of levonorgestrel (LNG) to plasma is desirable, furthermore, a sustained delivery of LNG along with rapid absorption will be necessary. The pharmacokinetics and pharmacodynamics of LNG entrapped in different kinds of liposome formulations via nasal administration in rats were evaluated and compared with LNG suspension via the oral route. The relative bioavailabilities of these liposome formulations via nasal administration were 100% or higher than 100%. The Cmax and Tmax values of sterylglucoside (SG) and chitosan-contained formulations by nasal administration were 416.84 ng/mL and 1.02 hr, 227.97 ng/mL and 2.02 hr, respectively, compared with that of 334.94 ng/mL and 1.89 hr of oral suspension. Fully 100% contraception was observed for all the formulations. SG could promote the absorption of LNG via the nasal route and may provide a rapid onset of action of LNG for emergency contraception. Chitosan could retain LNG in the nasal cavity for long contact time to sustain delivery of LNG. The rapid onset and sustained delivery of LNG can be achieved via the nasal route using liposomes as the vehicle.
Asunto(s)
Anticonceptivos Hormonales Poscoito/administración & dosificación , Anticonceptivos Hormonales Poscoito/farmacocinética , Levonorgestrel/administración & dosificación , Levonorgestrel/farmacocinética , Absorción , Adhesivos , Administración Intranasal , Animales , Área Bajo la Curva , Disponibilidad Biológica , Química Farmacéutica , Quitosano , Anticonceptivos Hormonales Poscoito/farmacología , Sistemas de Liberación de Medicamentos , Femenino , Levonorgestrel/farmacología , Liposomas , Mucosa Nasal/metabolismo , Ratas , Ratas WistarRESUMEN
BACKGROUND: In January 2001, emergency hormonal contraception was made available for women over the age of 16 years directly from a pharmacist without prescription. It is of interest whether this change in the UK has led to any improvements or deterioration in the service provided for the women who need it. METHODS: Self- completed, anonymous questionnaires were distributed to women requesting emergency hormonal contraception through a single group of pharmacies located throughout England, Wales and Scotland. RESULTS: A total 419 women returned completed questionnaires. A greater proportion of women were able to take emergency contraception within 24 h when they obtained their tablets directly from a pharmacy without a prescription (64% versus 46%, P = 0.029). Women who obtained their drugs directly from the pharmacist were just as well informed, just as likely to arrange regular follow-up and generally preferred this system, although they disliked having to pay. CONCLUSION: Making emergency hormonal contraception available without prescription has improved services to women who need them, but these improvements are quantitatively minimal, preventing only five additional pregnancies per 10,000 users.
Asunto(s)
Anticonceptivos Hormonales Poscoito/farmacología , Tratamiento de Urgencia , Medicamentos sin Prescripción/farmacología , Anticonceptivos Hormonales Poscoito/administración & dosificación , Anticonceptivos Hormonales Poscoito/economía , Esquema de Medicación , Costos de los Medicamentos , Inglaterra , Femenino , Conocimientos, Actitudes y Práctica en Salud , Accesibilidad a los Servicios de Salud , Humanos , Escocia , Encuestas y Cuestionarios , Comprimidos , GalesRESUMEN
The effect of aromatase inhibitors on the implantation process is not well known. This study examined the anti-implantation action in rats of a nonsteroidal aromatase inhibitor of high specific activity, fadrozole hydrochloride (Fad). Continuous subcutaneous infusion of Fad at 300 microg/day from Day 1 (the day of sperm detection) through Day 7 of pregnancy using a mini-osmotic pump was found to delay the initiation of implantation by 1 or 2 days with no negative effects on embryonic viability. The Fad treatment delayed preimplantation embryo development and zona shedding by embryos. The treatment also delayed the period of maximum sensitivity to a decidualizing stimulus (intraluminal infusion of sesame oil) by 2 days. The results show that continuous treatment with Fad has multiple anti-implantation effects in rats.
Asunto(s)
Implantación del Embrión/efectos de los fármacos , Fadrozol/farmacología , Animales , Inhibidores de la Aromatasa , Blastocisto/efectos de los fármacos , Anticonceptivos Hormonales Poscoito/farmacología , Inhibidores Enzimáticos/farmacología , Femenino , Viabilidad Fetal/efectos de los fármacos , Peso Fetal/efectos de los fármacos , Embarazo , Ratas , Ratas Sprague-DawleyRESUMEN
La intercepción postcoital se viene utilizando como medida contraceptiva secundaria de forma habitual desde hace años. La generalización de su uso podría disminuir la tasa de interrupciones de embarazos no deseados. En este trabajo se pretende revisar algunos conceptos sobre el manejo práctico de este tipo de tratamientos, incluyendo el uso de Levonorgestrel para esta indicación, recientemente introducido en nuestro país. (AU)
Asunto(s)
Femenino , Humanos , Anticonceptivos Poscoito/administración & dosificación , Anticonceptivos Poscoito/farmacología , Anticonceptivos Hormonales Poscoito/administración & dosificación , Anticonceptivos Hormonales Poscoito/farmacología , Levonorgestrel/administración & dosificación , Levonorgestrel/farmacologíaAsunto(s)
Anticonceptivos Sintéticos Orales , Congéneres de la Progesterona , Anticonceptivos Sintéticos Orales/administración & dosificación , Anticonceptivos Sintéticos Orales/efectos adversos , Anticonceptivos Sintéticos Orales/farmacología , Anticonceptivos Hormonales Poscoito/administración & dosificación , Anticonceptivos Hormonales Poscoito/efectos adversos , Anticonceptivos Hormonales Poscoito/farmacología , Anticonceptivos Sintéticos Poscoito/administración & dosificación , Anticonceptivos Sintéticos Poscoito/efectos adversos , Anticonceptivos Sintéticos Poscoito/farmacología , Preparaciones de Acción Retardada , Desogestrel/administración & dosificación , Desogestrel/efectos adversos , Desogestrel/farmacología , Implantes de Medicamentos , Femenino , Humanos , Inyecciones Intramusculares , Levonorgestrel/administración & dosificación , Levonorgestrel/efectos adversos , Levonorgestrel/farmacología , Ovulación/efectos de los fármacos , Congéneres de la Progesterona/administración & dosificación , Congéneres de la Progesterona/efectos adversos , Congéneres de la Progesterona/farmacología , Ensayos Clínicos Controlados Aleatorios como AsuntoRESUMEN
DL-Centchroman (67/20; INN: Ormeloxifene) synthesized at the Central Drug Research Institute, Lucknow, is a nonsteroidal once-a-week oral contraceptive. It was introduced in Delhi in July, 1991, marketed in India in 1992 as Saheli and Choice-7 (Hindustan Latex Ltd., Thiruvananthapuram) and Centron (Torrent Pharmaceuticals India Ltd., Ahmedabad), and included in the National Family Welfare Programme in 1995.5 According to post-marketing surveillance, approximately 100,000 women were using this pill and approximately 1100,000 menstrual cycles were covered until 1996. It is a unique need-oriented contraceptive being effective when taken immediately after coitus or routinely as a weekly pill and has the advantage of less frequent administration. Its contraceptive action is quickly reversible. It has long terminal serum halflife of 168 hr in women and exhibits duration of anti-implantation/estrogen antagonistic action of 120 hr, despite a short (24.1 hr) serum halflife, in the rat. In lactating women, it is excreted in milk in quantities considered unlikely to cause any deleterious effect on suckling babies. In phase II and III multicentric trials as a contraceptive, children born of method-and-user failure pregnancies showed normal milestones, without any congenital anomaly. Reports of its promising action in the management of certain hormone-related clinical disorders are available. It has an excellent therapeutic index and is considered safe for chronic administration.
Asunto(s)
Centcromano/farmacología , Anticonceptivos Hormonales Poscoito/farmacología , Antagonistas de Estrógenos/farmacología , Receptores de Estrógenos/efectos de los fármacos , Animales , Centcromano/síntesis química , Centcromano/farmacocinética , Anticonceptivos Hormonales Poscoito/síntesis química , Anticonceptivos Hormonales Poscoito/farmacocinética , Antagonistas de Estrógenos/síntesis química , Antagonistas de Estrógenos/farmacocinética , Femenino , Humanos , MasculinoAsunto(s)
Anticoncepción/tendencias , Anticonceptivos Hormonales Poscoito/uso terapéutico , Anticonceptivos Sintéticos Poscoito/uso terapéutico , Levonorgestrel/uso terapéutico , Mifepristona/uso terapéutico , Anticonceptivos Hormonales Poscoito/farmacología , Anticonceptivos Sintéticos Poscoito/farmacología , Femenino , Humanos , Levonorgestrel/farmacología , Mifepristona/farmacología , Resultado del TratamientoRESUMEN
Wide availability of hormonal postcoital contraception (HPC) is likely to reduce the incidence of unplanned pregnancies. The two most common indications for HPC are unprotected intercourse and 'condom accidents'. The combined estrogen/progestogen HPC described by Yuzpe is the most widely used method. It is given within 72 h of unprotected intercourse. The efficacy of combined HPC is high. The crude failure rate is 1-5 per 100 woman-months while the true reduction in pregnancy risk is over 75%. Efficacy is not influenced by the exposure-treatment interval within the 72-h 'window'. The mechanisms of action is multifocal and depends on the cycle phase at which treatment is instituted. Data are presented suggesting a consistent endometrial effect. None of the side-effects of HPC are serious. When HPC fails, there is so far no evidence of an adverse effect of the treatment on the outcome of pregnancy. Counselling should include all the above together with discussion of possible side-effects such as nausea and vomiting. The clinician should ensure that the woman uses an effective contraceptive thereafter. There is renewed interest in progestogen-only postcoital contraception. Varying doses of levonorgestrel have been used. The efficacy of some regimens is similar to that of the combined HPC. Danazol has not proved to be as effective. Antiprogestins hold the greatest promise of emergency contraception with high efficacy and low side-effects.
Asunto(s)
Anticonceptivos Hormonales Poscoito , Embarazo no Deseado , Condones/efectos adversos , Anticonceptivos Hormonales Poscoito/efectos adversos , Anticonceptivos Hormonales Poscoito/farmacología , Contraindicaciones , Femenino , Humanos , Selección de Paciente , Embarazo , Violación , TeratógenosRESUMEN
STUDY OBJECTIVE: To evaluate the effect of treatment with ethinylesteradiol-levonorgestrel or danazol on ovarian function, gonadotrophin release and endometrial development during the time when a pregnancy may occur following unprotected intercourse. METHODS: Women with regular menstrual cycles were followed during one control, one treatment and one follow-up month. The women obtained either a combination of 0.5 mg levonorgestrel and 0.1 mg ethinylestradiol (Yuzpe regimen: n = 16) or 600 mg danazol orally and repeated after 12 hours (n = 16). The treatment was administered on either cycle day (cd) 12 or day LH +2. An endometrial biopsy was obtained once on cd LH +6 to +8 in the subjects treated on cd LH +2 both in control and treatment cycles, and morphometric analysis was performed. The concentrations of LH, pregnandiol (P2G), and estrone (EIG) glucuronide were followed daily in morning urine during control and treatment cycles. RESULTS: Following treatment with the Yuzpe regimen on cd 12 the LH surge was either undetectable (three subjects), postponed to cd 16 to 22 (three subjects) or cd 38 to 39 (two subjects) with lower P2G and LH levels than in the control cycle. Following preovulatory treatment with danazol, no LH peak could be detected in four subjects and in the remaining four subjects the LH peak varied between cd 13 and cd 24. The mean area under the curve for LH was significantly lower, the levels of EIG were slightly higher and the P2G levels were unaffected in comparison with the control cycle. Neither of the two treatments administered on cd LH +2 affected the hormonal pattern and only a discreet effect on the development of the endometrium was seen after the EE/LNG treatment. CONCLUSION: The findings indicate that the contraceptive effect of postcoital treatment with EE/LNG and danazol is mainly due to an inhibition or delay of ovulation and insufficient corpus luteum function. The direct effect on the endometrium is limited, if any.
Asunto(s)
Anticonceptivos Hormonales Poscoito/farmacología , Anticonceptivos Sintéticos Poscoito/farmacología , Danazol/farmacología , Endometrio/efectos de los fármacos , Etinilestradiol/administración & dosificación , Etinilestradiol/farmacología , Levonorgestrel/administración & dosificación , Levonorgestrel/farmacología , Menstruación/efectos de los fármacos , Administración Oral , Combinación de Medicamentos , Endometrio/citología , Estrona/orina , Femenino , Humanos , Hormona Luteinizante/orina , Embarazo , Pregnanodiol/orinaRESUMEN
Steroid hormones from the testes promote attraction to estrous females and facilitate copulation in the male Syrian hamster. We compared the ability of testosterone (T) and MENT, a potent synthetic androgen that does not undergo 5 alpha-reduction, to maintain sexual behavior in castrated males. Steroid treatment was initiated immediately after castration at three levels by means of Alzet osmotic pumps in sexually experienced adult male hamsters. Daily doses were 5, 25, or 100 micrograms T and 1, 5, or 25 micrograms MENT (n = 5/group). Additional castrated males (n = 5) remained untreated. Sexual behavior was recorded during two 10-min tests before, and at 2, 4, 6, and 8 weeks after orchidectomy. MENT and T maintained equivalent levels of behavior at each corresponding dose of androgen (high, medium, or low). The low dose of T or MENT failed to sustain mating behavior. Eight weeks after castration, males receiving the high and medium doses of androgens continued to express intromissions and ejaculations at gonadally intact levels. However, only males receiving the high dose showed anogenital investigation at the same level as intact males. From these data, we conclude that MENT sustains mating behavior in the male hamster, and that chemoinvestigatory behavior requires higher levels of androgens than those necessary for copulation.
Asunto(s)
Anticonceptivos Hormonales Poscoito/farmacología , Nandrolona/análogos & derivados , Conducta Sexual Animal/efectos de los fármacos , Animales , Copulación/efectos de los fármacos , Cricetinae , Relación Dosis-Respuesta a Droga , Femenino , Masculino , Mesocricetus , Nandrolona/farmacología , Conducta SocialRESUMEN
Although postcoital contraception might aid in reducing the occurrence of some unintended pregnancies, it is seldom used. This review summarizes the development of postcoital methods, focusing on the Yuzpe regimen, the most widely used emergency contraceptive in the United States. The article discusses its mechanism of action, safety, side effects, and effectiveness. Reasons for its limited use are discussed, as are recent findings that RU 486 may be a superior postcoital agent. Finally, a protocol for integrating the Yuzpe method into nurse-midwifery practice is presented.
PIP: There are several contraceptive methods that can be used to prevent pregnancy after unprotected intercourse. US women rarely use them, however. Nurse-midwives should become familiar with postcoital contraceptive methods and consider providing them through their practice. The most common postcoital contraceptive method in the US is the Yuzpe regimen. The IUD can be been used but its high cost and restrictions to multiparous, monogamous women at low risk of sexually transmitted diseases limit its use as a postcoital contraceptive method. The Yuzpe regimen includes two doses of two oral contraceptive (OC) pills, each containing 50 mcg ethinyl estradiol and 0.5 mg norgestrel. Its failure rates range from 0.2% to 1.9%. No serious or long-term complications have been reported. Two common side effects are nausea and vomiting. Possible modes of action of the Yuzpe regimen are: blockage of the midcycle luteinizing hormone surge, alteration of corpus luteum function, or alteration of the endometrium resulting in implantation suppression. Two possible new drugs for postcoital contraception are mifepristone (RU-486) and danazol, a synthetic hormone resembling testosterone. Possible reasons why postcoital contraception is not used more widely include: lack of information about it among women and health care providers; lack of approval by the US Food and Drug Administration, which prohibits OC manufacturers from advertising the OC for postcoital use, and federally funded family planning services cannot use drugs for non-approved indications; adverse social attitudes toward sexuality and abortion; the fact that it is considered an early form of abortion; and limited evidence of its actual effectiveness. Nurse-midwives could follow a conservative approach when prescribing the Yuzpe regimen; for example, its use should only be voluntary and based on a woman's certainty she does not want to become pregnant.
Asunto(s)
Anticonceptivos Hormonales Poscoito/farmacología , Enfermeras Obstetrices , Protocolos Clínicos , Anticonceptivos Hormonales Poscoito/administración & dosificación , Danazol/farmacología , Esquema de Medicación , Etinilestradiol/farmacología , Combinación Etinil Estradiol-Norgestrel , Femenino , Humanos , Mifepristona/farmacología , Norgestrel/farmacologíaRESUMEN
OBJECTIVE: To evaluate the effect of high-dose oral contraceptives on serum and uterine luminal fluid progesterone-associated endometrial protein in the luteal phase. METHODS: Five ovulatory women participated in the study. In a control cycle, serum and uterine lavage samples were collected on luteal day 11. In the next cycle, on luteal day 9, the participants were given two 50-micrograms ethinyl estradiol-norgestrel tablets, repeated 12 hours later. Serum and uterine lavage samples were collected 48 hours (luteal day 11) after the last dose and analyzed by two-dimensional polyacrylamide gel electrophoresis and radioimmunoassays of the serum. RESULTS: Progesterone-associated endometrial protein levels were lower in sera from treated compared with control cycles. Analysis of serum levels of this protein by two-dimensional polyacrylamide gel electrophoresis did not reveal bands corresponding to the known size and charge characteristics (27 kd and pI of 4.9) in either control or treatment samples. On the other hand, in uterine lavage samples, a complete suppression of the 27-kd, pI-4.9 species was evident after treatment. CONCLUSION: High-dose ethinyl estradiol-norgestrel emergency contraception effectively suppresses progesterone-associated endometrial protein in the midluteal uterus, potentially altering the endometrial environment unfavorably and affecting the survival of the early embryo.