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2.
Eur J Contracept Reprod Health Care ; 20(3): 231-5, 2015 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-25798535

RESUMEN

OBJECTIVE: The study aimed to investigate the effect of concomitant use of atorvastatin or rosuvastatin on the pharmacokinetic and pharmacodynamic profile of centchroman, a non-steroidal female oral contraceptive. METHODS: A rat model was used to predict pharmacokinetic drug-drug interactions between centchroman and atorvastatin or rosuvastatin. A dried blood spot sampling technique followed by liquid chromatography-tandem mass spectrometry detection was employed for analysis of the pharmacokinetic interaction study samples. Sperm-positive female rats were investigated for postcoital contraceptive activity of centchroman with or without coadministration of atorvastatin or rosuvastatin. RESULTS: Coadministration of atorvastatin or rosuvastatin may increase the systemic availability of centchroman in blood, but it does not affect the pharmacodynamic profile of centchroman. CONCLUSION: Atorvastatin or rosuvastatin may be prescribed with centchroman without compromising the contraceptive efficacy of centchroman.


Asunto(s)
Atorvastatina/farmacología , Centcromano/farmacocinética , Anticonceptivos Sintéticos Poscoito/farmacocinética , Inhibidores de Hidroximetilglutaril-CoA Reductasas/farmacología , Rosuvastatina Cálcica/farmacología , Animales , Atorvastatina/administración & dosificación , Centcromano/administración & dosificación , Cromatografía Líquida de Alta Presión , Anticonceptivos Orales/administración & dosificación , Anticonceptivos Sintéticos Poscoito/administración & dosificación , Femenino , Inhibidores de Hidroximetilglutaril-CoA Reductasas/administración & dosificación , Ratas , Ratas Sprague-Dawley , Rosuvastatina Cálcica/administración & dosificación
3.
Reprod Biol ; 14(3): 224-33, 2014 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-25152521

RESUMEN

RU486 is a partial progesterone and estrogen receptor antagonist, functioning to actively silence progesterone receptor gene-associated transcription. For this reason, it has been used as both a contraceptive and an abortive agent. In the present study, cellular and gene specific effects of RU486 were investigated in a rat model of early pregnancy, including key phases of the window of receptivity and early implantation. As these stages are hormonally regulated by progesterone and estrogens, the focus here was to elucidate the mechanism of action of a single dose of RU486, used as a postcoital contraceptive, to successfully prevent implantation of a viable blastocyst. Immunofluorescent techniques were used to examine the change in protein levels of PR in RU486-treated endometria at days 4.5, 5.5 and 6.5 of pregnancy. Changes in the Pgr gene expression level as a consequence of RU486 administration was evaluated using quantitative real-time reverse transcription polymerase chain reaction. The progesterone receptor gene and protein expression was ubiquitously decreased throughout pregnancy as a direct consequence of RU486 administration. The overall effects of postcoital RU486 administration during early pregnancy indicate highly effective inhibition of progesterone and estrogen effects on the endometrium, mediated by their receptors. More specifically, the expression and localization of the progesterone receptor mirrors that described in ovariectomized animal models, suggesting a hormonally under-stimulated endometrium. Clearly from the present study, the precise priming of the endometrium by progesterone, in preparation for blastocyst implantation, is severely impaired by RU486, thus predisposing the uterus to pregnancy failure.


Asunto(s)
Anticonceptivos Sintéticos Poscoito , Implantación del Embrión/efectos de los fármacos , Endometrio/efectos de los fármacos , Regulación del Desarrollo de la Expresión Génica/efectos de los fármacos , Mifepristona , Progesterona/antagonistas & inhibidores , Receptores de Progesterona/antagonistas & inhibidores , Animales , Anticonceptivos Sintéticos Poscoito/administración & dosificación , Endometrio/citología , Endometrio/metabolismo , Antagonistas del Receptor de Estrógeno/administración & dosificación , Femenino , Técnica del Anticuerpo Fluorescente Indirecta , Inyecciones Subcutáneas , Mifepristona/administración & dosificación , Embarazo , Progesterona/metabolismo , Transporte de Proteínas/efectos de los fármacos , Ratas Wistar , Receptores de Progesterona/genética , Receptores de Progesterona/metabolismo , Transducción de Señal/efectos de los fármacos
4.
Contraception ; 90(1): 29-35, 2014 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-24815098

RESUMEN

OBJECTIVES: We tested the effectiveness and feasibility of remote communication technologies to increase follow-up after early medical abortion. STUDY DESIGN: Women (n=999) were randomized to 'remote' follow-up incorporating a low-sensitivity pregnancy test and standardized symptom questionnaire administered online, by text message or telephone by a non-clinical call center operator 2 weeks after treatment, or to 'clinic-based' follow-up with ultrasound at 1 week. Women in the clinic-based group who could not return performed a high-sensitivity pregnancy test at 3 weeks and had a telephone call with clinic staff. The primary outcome was completion of follow-up. Rates of complications, acceptability and preferences were compared. RESULTS: The overall follow-up rate did not differ by group {clinic-based, 73% vs. remote, 69%; risk ratio (RR) 1.0 [95% confidence interval (CI) 0.9-1.2]}. In the clinic-based group, 83% did not return for an ultrasound scan and were followed up by phone. In the remote group, follow-up by phone or text was more successful than online (text: 75.4%; phone: 73.7%; online: 46.5%, p<.001). The proportion of women receiving additional care was 9% in the clinic-based group and was 4% in the remote group [RR 1.8 (95% CI 1.1-3.1)]. Most women found their follow-up method acceptable but would prefer follow-up by phone or text message if needed in future. CONCLUSIONS: Follow-up after medical abortion using remote communication is feasible and, for most women, preferable to a clinic visit. IMPLICATIONS: Medical abortion protocols typically use follow-up visits to ensure early identification of complications. This study demonstrates that follow-up can be achieved using remote communication technologies. This model may reduce the burden of multiple clinic visits on patients and providers.


Asunto(s)
Aborto Inducido/métodos , Comunicación , Anticonceptivos Sintéticos Poscoito/administración & dosificación , Mifepristona/administración & dosificación , Adolescente , Adulto , Intervalos de Confianza , Femenino , Estudios de Seguimiento , Humanos , Modelos Logísticos , Persona de Mediana Edad , Satisfacción del Paciente , Embarazo , Encuestas y Cuestionarios , Teléfono , Envío de Mensajes de Texto , Reino Unido , Adulto Joven
5.
Gynecol Endocrinol ; 29 Suppl 1: 1-14, 2013 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-23437846

RESUMEN

There have been numerous attempts to control fertility after unprotected sexual intercourse (UPSI). From very bizarre methods like the vaginal application of Coca Cola to the more serious attempts using calcium antagonists influencing fertility parameters in sperm to hormonal methods or intrauterine devices. So far, hormonal methods preventing or delaying ovulation have proved to be the most popular starting with the combination of ethinyl estradiol and levonorgestrel (LNG), known as the Yuzpe regimen. The first dose had to be taken within 72 hours of UPSI, a second one 12 hours later. Later on, LNG alone, at first in a regimen similar to the Yuzpe method (2 × 0.75 mg 12 hours apart) showed to be more successful, eventually resulting in the development of a 1.5 mg LNG pill that combined good efficacy with a high ease of use. Several efficacious and easy to use methods for emergency contraception (EC) are available on the market today with the most widely spread being LNG in a single dose of 1.5 mg (given as one tablet of 1.5 mg or 2 tablets of 0.75 mg each) for administration up to 3 days (according to WHO up to 5 days) after UPSI. Its limitations are the non-optimal efficacy which is decreasing the later the drug is taken and the fact that it is only approved for up to 72 hours after UPSI. This regimen has no effect on the endometrium, corpus luteum function and implantation, is not abortive and don't harm the fetus if accidentally taken in early pregnancy. It has no impact on the rate of ectopic pregnancies. It has become the standard method used up to this day in most countries. Since the mid 1970s copper IUDs have been used for EC, which show a high efficacy. Their disadvantages lie in the fact that EC is considered an off label use for most IUDs (not for the GynFix copper IUD in the European Union) and that they might not be acceptable for every patient. Furthermore IUD-insertion is an invasive procedure and it is required trained providers and sterilized facilities. Mifepristone in the dosages of 10 or 25 mg is used with good results as an emergency contraceptive in China for up to 120 hours after UPSI, but has never received any significant consideration in Western countries. While high doses of mifepristone has an effect on endometrial receptivity and will inhibit ovulation if given in the follicular phase and prevent implantation if given in the early luteal phase, low doses such as 10 mg has no impact on the endometrium. Mifepristone does not increase the rate of ectopic pregnancies. The most recent development is the approval of the selective progesterone receptor modulator ulipristal acetate (UPA) in the dosage of 30 mg for EC up to 5 days after UPSI, combining the safe and easy application of the single dose LNG pill with an even higher efficacy. It has shown to be more efficacious than LNG and can be used for up to 120 hours after UPSI; the difference in efficacy is highest for 0-24 hours, followed by 0-72 hours following UPSI. No VTE has been reported following UPA-administration or any progesterone receptor modulator. No effect on endometrium, corpus luteum function and implantation has been observed with doses used for EC. Independent of the substance it should be noted that, if there is a choice, the intake of an oral emergency contraceptive pill should happen as soon as possible after the risk situation. A pre-existing pregnancy must be excluded. Possible contraindications and drug interactions must be considered according to the individual special product informations.


Asunto(s)
Anticoncepción Postcoital , China , Anticoncepción Postcoital/efectos adversos , Anticoncepción Postcoital/métodos , Anticonceptivos/administración & dosificación , Anticonceptivos Poscoito/administración & dosificación , Anticonceptivos Sintéticos Poscoito/administración & dosificación , Etinilestradiol/administración & dosificación , Etinilestradiol/efectos adversos , Unión Europea , Femenino , Humanos , Dispositivos Intrauterinos de Cobre/efectos adversos , Levonorgestrel/administración & dosificación , Levonorgestrel/efectos adversos , Mifepristona/administración & dosificación , Mifepristona/efectos adversos , Norpregnadienos/administración & dosificación , Norpregnadienos/efectos adversos , Ovulación/efectos de los fármacos , Embarazo , Embarazo Ectópico , Receptores de Progesterona/efectos de los fármacos , Factores de Tiempo
7.
Adv Physiol Educ ; 36(1): 34-41, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-22383410

RESUMEN

To systematically investigate whether the inclusion of a bioethical discussion improves the learning and retention of biological content, students in two sections of an introductory zoology class were taught the biology behind emergency contraception and RU-486. Students in one section of the course participated in a bioethical discussion, whereas students in the other section participated in a content-only discussion. Pre- and postsurveys, response paragraphs, and a final exam were collected and used to examine the learning and retention of content knowledge. Results suggested that students who participated in a bioethical discussion of emergency contraception and RU-486 learned and retained information better than students who received content-only instruction. Interestingly, students who participated in the bioethical discussion also appeared to be more confident in their answers. The results of this study may inform the teaching practices and goals of science educators who would like to incorporate a discussion of bioethical issues into their curriculum but often feel that content coverage is paramount.


Asunto(s)
Bioética/educación , Disciplinas de las Ciencias Biológicas/ética , Anticoncepción Postcoital/ética , Anticonceptivos Sintéticos Poscoito/administración & dosificación , Aprendizaje , Mifepristona/administración & dosificación , Retención en Psicología , Adolescente , Adulto , Disciplinas de las Ciencias Biológicas/educación , Femenino , Humanos , Masculino , Adulto Joven
8.
Contraception ; 84(6): 642-8, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-22078196

RESUMEN

BACKGROUND: This study was conducted to observe the in vivo effect of 4-(2-aminoethyl)benzenesulfonyl fluoride hydrochloride (AEBSF) on embryo implantation in rats and its in vitro effect on cell adhesion. STUDY DESIGN: The anti-implantation efficacy of AEBSF in rats was determined by counting the number of visible implanted embryos on day 8 of pregnancy following intrauterine (5 mg and 10 mg AEBSF per horn) or tail vein (10 mg AEBSF per rat) administration on day 3 of pregnancy. The effects of AEBSF on cell adhesion were detected, respectively, by using the mouse blastocysts-endometrial cells or the human umbilical vein endothelial cells (HUVECs)-HeLa cells co-culture model. The alteration in protein secretion pattern of HUVECs and HeLa cells was detected by the proteome analysis. RESULTS: 4-(2-Aminoethyl)benzenesulfonyl fluoride hydrochloride showed an in vivo inhibitory effect on embryo implantation in rat. In vitro, AEBSF could disturb the growth of blastocysts on endometrial cells and inhibit the adhesion of HeLa cells on HUVECs. The treatment of AEBSF could alter the protein secretion pattern of co-cultured HUVEC-HeLa cells. CONCLUSION: 4-(2-Aminoethyl)benzenesulfonyl fluoride hydrochloride might be a potential leading compound for novel contraceptives, and its inhibitory effect on implantation might result from the interference in extracellular matrix remodeling process.


Asunto(s)
Implantación del Embrión/efectos de los fármacos , Inhibidores de Serina Proteinasa/farmacología , Sulfonas/farmacología , Administración Intravaginal , Animales , Blastocisto/efectos de los fármacos , Adhesión Celular/efectos de los fármacos , Células Cultivadas , Técnicas de Cocultivo , Anticonceptivos Sintéticos Poscoito/administración & dosificación , Anticonceptivos Sintéticos Poscoito/farmacología , Relación Dosis-Respuesta a Droga , Endometrio/citología , Endometrio/efectos de los fármacos , Femenino , Células HeLa , Células Endoteliales de la Vena Umbilical Humana/efectos de los fármacos , Humanos , Inyecciones Intravenosas , Ratones , Ratones Endogámicos ICR , Embarazo , Distribución Aleatoria , Ratas , Ratas Sprague-Dawley , Inhibidores de Serina Proteinasa/administración & dosificación , Sulfonas/administración & dosificación
9.
Eur J Contracept Reprod Health Care ; 16(5): 403-6, 2011 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-21777048

RESUMEN

OBJECTIVES: Centchroman (Ormeloxifene) is a synthetic non-steroidal compound used as an oral and a post-coital contraceptive. It is currently under trial for treatment of breast cancer and postmenopausal osteoporosis. Centchroman has been reported to induce only minimal side effects and no hormonal imbalance. CASE: A young woman who used centchroman for a long time in an unsupervised fashion presented with menorrhagia, which was controlled with norethisterone. Her massively enlarged uterus showed extensive decidual changes in a hyperplastic endometrium, and diffuse microglandular cervical hyperplasia. CONCLUSIONS: The case suggests a prominent oestrogenic effect of centchroman on the uterus. This could be a significant adverse effect related to prolonged therapy. Lengthy intake of centchroman requires medical surveillance and long-term studies are needed.


Asunto(s)
Centcromano/efectos adversos , Anticonceptivos Sintéticos Poscoito/efectos adversos , Antagonistas de Estrógenos/efectos adversos , Menorragia/diagnóstico , Adulto , Centcromano/administración & dosificación , Anticonceptivos Sintéticos Poscoito/administración & dosificación , Diagnóstico Diferencial , Esquema de Medicación , Antagonistas de Estrógenos/administración & dosificación , Femenino , Humanos , Menorragia/inducido químicamente
10.
Contraception ; 82(5): 442-52, 2010 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-20933118

RESUMEN

Administration of mifepristone followed by the prostaglandin, misoprostol, has been used successfully in the medical termination of pregnancy for over 25 years, and the method is registered in 35 countries. Single doses of mifepristone are also effective as an emergency postcoital contraceptive. Mifepristone administered for 3 months or longer to women with uterine leiomyomas, is associated with a reduction in pain and bleeding with improvement in quality of life and decrease in fibroid size. Mifepristone is also effective in decreasing pain in women with endometriosis. In both these conditions, serum estradiol levels are in the range of those in the early follicular phase. A daily dose of at least 2 mg mifepristone blocks ovulation. In contrast, weekly administration of 25 or 50 mg does not consistently block ovulation but has contraceptive potential by delaying endometrial development. Mifepristone in a dose of 200 mg, administered 48 h after the Luteinizing Hormone (LH) surge, also acts as a contraceptive, but this strategy is not practical for widespread use. Administration of mifepristone for 4-6 months or longer may lead to endometrial thickening. Endometrial histology reveals cystic glandular dilation together with admixed estrogen (mitotic) and progestin (secretory) epithelial effects. This histological pattern does not represent endometrial hyperplasia.


Asunto(s)
Mifepristona , Receptores de Progesterona/antagonistas & inhibidores , Abortivos Esteroideos/administración & dosificación , Abortivos Esteroideos/efectos adversos , Abortivos Esteroideos/farmacología , Aborto Legal , Animales , Antineoplásicos Hormonales/administración & dosificación , Antineoplásicos Hormonales/efectos adversos , Antineoplásicos Hormonales/farmacología , Anticonceptivos Sintéticos Poscoito/administración & dosificación , Anticonceptivos Sintéticos Poscoito/efectos adversos , Anticonceptivos Sintéticos Poscoito/farmacología , Femenino , Enfermedades de los Genitales Femeninos/tratamiento farmacológico , Humanos , Mifepristona/administración & dosificación , Mifepristona/efectos adversos , Mifepristona/farmacología , Embarazo , Receptores de Progesterona/agonistas , Salud de la Mujer
11.
Contraception ; 82(4): 373-8, 2010 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-20851232

RESUMEN

BACKGROUND: Unplanned pregnancies are common in Nigeria. Much of the unplanned pregnancies is due to low contraceptive prevalence and high contraceptive user failure rates. High user failure rates suggest the important role of emergency contraception to prevent unplanned pregnancy. STUDY DESIGN: Randomized, controlled, double-blind, multicenter, noninferiority trial comparing efficacy and side effects of two emergency contraceptive regimens up to 5 days after unprotected intercourse among 3022 Nigerian women: levonorgestrel administered in two doses of 0.75 mg given 12 h apart and levonorgestrel administered in a single dose of 1.5 mg. RESULTS: Efficacy was similar between the treatment groups; post-treatment pregnancy proportions were 0.57% in the two-dose regimen vs. 0.64% in the single-dose regimen (risk difference 0.07% (95% CI -0.50 to 0.64). The majority of women menstruated the first day of expected menses and the groups did not differ regarding reported side effects. CONCLUSIONS: This study shows the simplified emergency contraceptive regimen of single-dose levonorgestrel is not inferior in efficacy to the two-dose regimen among Nigerian women.


Asunto(s)
Anticoncepción Postcoital/métodos , Anticonceptivos Sintéticos Poscoito/administración & dosificación , Levonorgestrel/administración & dosificación , Adulto , Método Doble Ciego , Esquema de Medicación , Femenino , Humanos , Modelos Logísticos , Nigeria , Embarazo , Factores de Tiempo , Adulto Joven
12.
Hum Reprod ; 25(9): 2256-63, 2010 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-20634186

RESUMEN

BACKGROUND: Current methods of hormonal emergency contraception (EC) are ineffective in preventing follicular rupture when administered in the advanced pre-ovulatory phase. This study was designed to determine the capacity of ulipristal acetate (UPA), a selective progesterone receptor modulator developed for EC, to block follicular rupture when administered with a follicle of >or=18 mm. METHODS: This was a double-blind, crossover, randomized, placebo-controlled study. Thirty-five women contributed with UPA (30 mg. oral) and a placebo cycle. Serial blood sampling for luteinizing hormone (LH), estradiol and progesterone measurements and follicular monitoring by ultrasound were performed before and for 5 days following treatment. Follicular rupture inhibition was assessed in the overall study population and in subgroups of women stratified by when treatment was administered in relation to LH levels (before the onset of the LH surge, after the onset of the surge but before the LH peak or after the LH peak). RESULTS: Follicular rupture failed to occur for at least 5 days following UPA administration in 20/34 cycles [59%; 95% confidence interval (CI) (40.7-75.4%)], whereas rupture took place in all cycles within 5 days of placebo intake. When UPA was administered before the onset of the LH surge, or after the onset but before the LH peak, follicle rupture had not occurred within 5 days in 8/8 (100%) and 11/14 [78.6%; 95% CI (49.2-95.3)] cycles, respectively. In contrast, when UPA was given after the LH peak, follicle rupture inhibition was only observed in 1/12 [8.3%; 95% CI (0.2-38.5)] cycles. CONCLUSIONS: This study demonstrates that UPA can significantly delay follicular rupture when given immediately before ovulation. This new generation EC compound could possibly prevent pregnancy when administered in the advanced follicular phase, even if LH levels have already begun to rise, a time when levonorgestrel EC is no longer effective in inhibiting ovulation.


Asunto(s)
Anticoncepción Postcoital/métodos , Anticonceptivos Sintéticos Poscoito/uso terapéutico , Fase Folicular/efectos de los fármacos , Norpregnadienos/administración & dosificación , Norpregnadienos/uso terapéutico , Folículo Ovárico/efectos de los fármacos , Inhibición de la Ovulación/efectos de los fármacos , Adulto , Anticoncepción Postcoital/efectos adversos , Anticonceptivos Sintéticos Poscoito/administración & dosificación , Anticonceptivos Sintéticos Poscoito/efectos adversos , Estudios Cruzados , Método Doble Ciego , Estradiol/sangre , Femenino , Fase Folicular/sangre , Humanos , Hormona Luteinizante/sangre , Norpregnadienos/efectos adversos , Tamaño de los Órganos , Folículo Ovárico/anatomía & histología , Folículo Ovárico/diagnóstico por imagen , Progesterona/sangre , Receptores de Progesterona/antagonistas & inhibidores , Estadística como Asunto , Factores de Tiempo , Ultrasonografía , Adulto Joven
14.
Artículo en Español | LILACS, BINACIS | ID: biblio-1171275

RESUMEN

A pesar de lo extendido del uso de la anticoncepción de emergencia (AE) con levonorgestrel (LNG) en el mundo, el mecanismo de acción continúa siendo discutido, lo que ha sido aprovechado para que grupos confesionales aaquen su uso, argumentando que la misma es abortiva. Actualmente, dos comprimido de LNG de 0,75 mg hasta 5 días posteriores al coito no protegido, ha sido recomendada y mostrada como eficaz para AE. El mecanismo de acción probablemente depende del momento de la toma en relación al día del ciclo menstrual. Cuando el LNG para AE es administrado antes del período ovulatorio, el mismo inhibe la ovulación en algunas mujeres y afecta el endometrio. Sin embargo la administración de LNG antes de la ruptura folicular no mostró tener influencia sobre la expresión de glicodelina-A en biopsias de endometrio tomadas 24 o 48 horas después de la toma de las píldoras de LNG. Los resultados de los estudios no apoyan la idea de que el LNG como AE causaría un efecto anti-implantatorio. Fue especulado que el LNG podría actuar sobre los espermatozoides. En estudios muy antiguos de la Argentina fue observado que la administración de 0,4 mg de LNG dado 3-10 horas post coito reducía el número de espermatozoides recuperados de la cavidad uterina, causaba alcalinización del fluido intrauterino, inmovilizaba los espermatozoides y aumentaba la viscosidad del moco cervical. Esto llevó a sugerir que la migración espermática a los lugares de fertilización podría esar comprometida después de la ingesta de LNG como AE. Sin embargo, nosotros hemos trabajado sobre esta hipótesis, pero no observamos efectos sobre reacción acrosomal después de la exposición in vitro al LNG de espermatozoides capacitados...


Asunto(s)
Femenino , Humanos , Levonorgestrel/administración & dosificación , Levonorgestrel/farmacología , Levonorgestrel/uso terapéutico , Anticonceptivos Femeninos/administración & dosificación , Anticonceptivos Femeninos/farmacocinética , Anticonceptivos Femeninos/uso terapéutico , Anticonceptivos Hormonales Poscoito/administración & dosificación , Anticonceptivos Hormonales Poscoito/farmacocinética , Anticonceptivos Hormonales Poscoito/uso terapéutico , Anticonceptivos Sintéticos Poscoito/administración & dosificación , Anticonceptivos Sintéticos Poscoito/farmacocinética , Anticonceptivos Sintéticos Poscoito/uso terapéutico
15.
Artículo en Español | BINACIS | ID: bin-124029

RESUMEN

A pesar de lo extendido del uso de la anticoncepción de emergencia (AE) con levonorgestrel (LNG) en el mundo, el mecanismo de acción continúa siendo discutido, lo que ha sido aprovechado para que grupos confesionales aaquen su uso, argumentando que la misma es abortiva. Actualmente, dos comprimido de LNG de 0,75 mg hasta 5 días posteriores al coito no protegido, ha sido recomendada y mostrada como eficaz para AE. El mecanismo de acción probablemente depende del momento de la toma en relación al día del ciclo menstrual. Cuando el LNG para AE es administrado antes del período ovulatorio, el mismo inhibe la ovulación en algunas mujeres y afecta el endometrio. Sin embargo la administración de LNG antes de la ruptura folicular no mostró tener influencia sobre la expresión de glicodelina-A en biopsias de endometrio tomadas 24 o 48 horas después de la toma de las píldoras de LNG. Los resultados de los estudios no apoyan la idea de que el LNG como AE causaría un efecto anti-implantatorio. Fue especulado que el LNG podría actuar sobre los espermatozoides. En estudios muy antiguos de la Argentina fue observado que la administración de 0,4 mg de LNG dado 3-10 horas post coito reducía el número de espermatozoides recuperados de la cavidad uterina, causaba alcalinización del fluido intrauterino, inmovilizaba los espermatozoides y aumentaba la viscosidad del moco cervical. Esto llevó a sugerir que la migración espermática a los lugares de fertilización podría esar comprometida después de la ingesta de LNG como AE. Sin embargo, nosotros hemos trabajado sobre esta hipótesis, pero no observamos efectos sobre reacción acrosomal después de la exposición in vitro al LNG de espermatozoides capacitados...(AU)


Asunto(s)
Humanos , Femenino , Levonorgestrel/administración & dosificación , Levonorgestrel/farmacología , Levonorgestrel/uso terapéutico , Anticonceptivos Hormonales Poscoito/administración & dosificación , Anticonceptivos Hormonales Poscoito/farmacocinética , Anticonceptivos Hormonales Poscoito/uso terapéutico , Anticonceptivos Sintéticos Poscoito/administración & dosificación , Anticonceptivos Sintéticos Poscoito/farmacocinética , Anticonceptivos Sintéticos Poscoito/uso terapéutico , Anticonceptivos Femeninos/administración & dosificación , Anticonceptivos Femeninos/farmacocinética , Anticonceptivos Femeninos/uso terapéutico
16.
Contraception ; 77(6): 431-4, 2008 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-18477493

RESUMEN

BACKGROUND: The study was conducted to assess the bioavailability of two formulations of mifepristone in capsule and tablet forms at a single dose of 75 mg (half the registered dose in China). STUDY DESIGN: A randomized two-way crossover study was conducted in 18 healthy nonpregnant women. Each subject was orally given a single dose of mifepristone at 75 mg in capsule or tablet form on an alternate basis. Serial blood samples were collected over a period of 96 h and assayed for the plasma concentration of mifepristone by high-performance liquid chromatography. Paired t tests were used to compare the capsule and tablet forms in terms of maximum concentration (C(max)), time to maximum concentration (T(max)) and area under the curve over 96 h (AUC(0-96 h)). Relative bioavailability (capsule/tablet) was derived from AUC(0-96 h). Bioequivalability was analyzed by two one-sided t tests. RESULTS: The major pharmacokinetic parameters were as follows: C(max) values were 1.26+/-0.38 and 1.25+/-0.40 mcg/mL, T(max) values were 0.94+/-0.34 and 0.89+/-0.47 h, T(1/2Ke) values were 36.2+/-21.0 and 33.4+/-12.3 h and AUC((0-96 h)) values were 19.7+/-6.4 and 19.6+/-9.9 mcg.h/mL for mifepristone in capsule and tablet forms, respectively. No significant difference was observed among these parameters. The relative bioavailability was 109.4+/-34.8%. CONCLUSION: This study suggests that the two formulations of mifepristone are bioequivalent, which provides pharmacokinetic evidence for further reducing the dosage of mifepristone in clinical use.


Asunto(s)
Anticonceptivos Sintéticos Poscoito/administración & dosificación , Anticonceptivos Sintéticos Poscoito/farmacocinética , Mifepristona/administración & dosificación , Mifepristona/farmacocinética , Administración Oral , Adulto , Disponibilidad Biológica , Cápsulas , Cromatografía Liquida , Estudios Cruzados , Femenino , Humanos , Comprimidos
17.
Contraception ; 77(5): 328-32, 2008 May.
Artículo en Inglés | MEDLINE | ID: mdl-18402847

RESUMEN

BACKGROUND: This study was conducted to evaluate the effects of levonorgestrel administration for emergency contraception (EC) on bleeding pattern and pituitary-ovarian function. STUDY DESIGN: In 69 women with a reported stable menstrual cycle length of 24-34 days, we investigated bleeding patterns following EC administration in the follicular (n=26), periovulatory (n=14) and luteal (n=29) phase. In a subgroup of 8 women, hormonal evaluation and ultrasonography were performed. RESULTS: EC taken in the follicular, but not in the periovulatory or luteal phase, significantly shortened cycle length by 10.9+/-1 days. The subsequent cycle was not affected. EC taken in the late preovulatory phase, prior to the gonadotrophin surge, suppressed ovulation (n=7), while ovulation was not blocked when EC was given during an ongoing luteinizing hormone (LH) pulse (n=1). CONCLUSIONS: Our data indicate that EC given before the onset of the luteinizing hormone (LH) surge inhibits ovulation and hastens the end of the current menstrual cycle. Subsequently, the length of the following menstrual cycle returned as prior to treatment. By contrast, levonorgestrel administered after the expected ovulation has no effect on menstrual cycle length.


Asunto(s)
Anticonceptivos Sintéticos Poscoito/administración & dosificación , Levonorgestrel/administración & dosificación , Ciclo Menstrual/efectos de los fármacos , Ovario/efectos de los fármacos , Hipófisis/efectos de los fármacos , Adolescente , Adulto , Anticoncepción Postcoital , Estradiol/sangre , Femenino , Hormona Folículo Estimulante/sangre , Fase Folicular/efectos de los fármacos , Humanos , Fase Luteínica/efectos de los fármacos , Hormona Luteinizante/sangre , Ciclo Menstrual/sangre , Ovario/metabolismo , Ovulación/efectos de los fármacos , Hipófisis/metabolismo , Progesterona/sangre
19.
Hum Reprod ; 22(8): 2190-5, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17537781

RESUMEN

BACKGROUND: The objectives were firstly to assess acrosome reaction (AR) status of spermatozoa following uterine flushing, secondly to measure levonorgestrel (LNG) levels in serum and in uterine flushing fluid and finally to measure endometrial glycodelin-A expression after administration of LNG as a form of emergency contraception (EC). METHODS: Forty-eight experiments were conducted on 15 regularly menstruating women. Four groups were formed based on different intercourse to treatment interval and treatment to recovery of spermatozoa and the biopsies. RESULTS: Twenty-four and forty-eight hours after treatment, there were 14.5 +/- 3.9 x 10(6) and 17.3 +/- 6.8 x 10(6) sperm recovered from the uterus, respectively. There were no differences between the AR rate and the endometrial glycodelin-A staining intensity in an LNG or placebo treated cycles. The LNG in uterine flushing medium represented 1.38% of the values observed in serum 24 h after the LNG intake. CONCLUSIONS: Twenty-four and forty-eight hours after administration of EC, neither the proportion of AR sperm, nor the glycodelin-A level was influenced by 1.5 mg of LNG. LNG did not impair the cervical mucus either because viable spermatozoa were found in the genital tract 36-60 h after coitus and 24-48 h after LNG intake. The mechanism of action of LNG as EC remains unknown.


Asunto(s)
Reacción Acrosómica/fisiología , Anticoncepción Postcoital , Anticonceptivos Sintéticos Poscoito/administración & dosificación , Endometrio/metabolismo , Glicoproteínas/biosíntesis , Levonorgestrel/administración & dosificación , Proteínas Gestacionales/biosíntesis , Adulto , Método Doble Ciego , Endometrio/efectos de los fármacos , Femenino , Glicodelina , Humanos , Levonorgestrel/sangre , Masculino
20.
Contraception ; 75(6): 454-60, 2007 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-17519152

RESUMEN

OBJECTIVE: The study was conducted to assess levonorgestrel (LNG) serum levels achieved after a single administration of two different doses of Carraguard vaginal gel containing LNG (CARRA/LNG), designed for use as microbicide and contraceptive for potential dual protection. MATERIALS AND METHODS: This was a randomized double-blind pharmacokinetic study conducted in 12 subjects enrolled at two centers. Each subject received a single vaginal administration of CARRA/LNG containing either 0.75 or 1.5 mg LNG per 4 mL of gel on Days 10-12 of the menstrual cycle. LNG serum levels were measured at 0, 1, 2, 4, 8 and 12 h after administration and for the following 7 days. LH and progesterone (for a preliminary evaluation of effect on the ovarian function) as well as SHBG were measured in the daily samples. RESULTS: Serum LNG maximum concentrations (Cmax) were 14.1+/-2.1 and 11.7+/-2.7 nmol/L and Tmax was 12.0 and 6.0 h for the low and high dose, respectively, with large intersubject variability within the first 48 h. Mean levels at 96 h were 10% of Cmax. Differences in AUC between both doses were not statistically significant. SHBG levels decreased approximately 25% by Day 4 after administration. Luteal activity was observed in 3/6 and 5/6 of the subjects in the low- and high-dose group, respectively. CONCLUSION: This study demonstrates that the CARRA/LNG gel can sustain elevated serum levels of the contraceptive steroid for up to 96 h after a single application. The serum levels attained with the 0.75-mg formulation are in the range expected to perturb the ovulatory process as observed in some subjects. The lack of correlation between the administered dose and serum concentrations of the steroid may be related to a rate-limiting absorption of LNG from the vaginal mucosa. The results reported here suggest that the CARRA/LNG formulation has good potential to become a dual-protection method, possibly preventing conception and sexually transmitted infections.


Asunto(s)
Antiinfecciosos/farmacocinética , Levonorgestrel/farmacocinética , Administración Intravaginal , Antiinfecciosos/administración & dosificación , Antiinfecciosos/sangre , Área Bajo la Curva , Química Farmacéutica , Chile , Anticonceptivos Sintéticos Poscoito/administración & dosificación , Anticonceptivos Sintéticos Poscoito/sangre , Anticonceptivos Sintéticos Poscoito/farmacocinética , República Dominicana , Método Doble Ciego , Femenino , Humanos , Absorción Intestinal , Levonorgestrel/administración & dosificación , Levonorgestrel/sangre , Cremas, Espumas y Geles Vaginales
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