| 词条 | Ethinylestradiol/etonogestrel |
| 释义 |
| image = Vaginal Ring Application (Step 1).png | caption = Vaginal ring application (step 1) | type = combo | component1 = Ethinylestradiol | class1 = Estrogen | component2 = Etonogestrel | class2 = Progestogen | tradename = NuvaRing, others | Drugs.com = {{drugs.com|CONS|nuvaring}} | MedlinePlus = a604032 | licence_EU = | licence_US = | DailyMedID = | pregnancy_AU = | pregnancy_US = X | pregnancy_category= | legal_AU = | legal_CA = | legal_UK = | legal_US = Rx-only | legal_status = | routes_of_administration = Vaginal (ring) | CAS_number = 131562-74-8 | CAS_supplemental = | ATCvet = | ATC_prefix = | ATC_suffix = | ATC_supplemental = | PubChem = 9960701 | PubChemSubstance = | IUPHAR_ligand = | DrugBank = | ChemSpiderID = None | UNII = | KEGG = | ChEBI = | ChEMBL = | synonyms = }}Ethinylestradiol/etonogestrel (brand names NuvaRing) is a contraceptive vaginal ring containing the estrogen ethinylestradiol and the progestin etonogestrel which is marketed in the United States and Europe.[1] A study found that users of vaginal rings with ethinylestradiol and etonogestrel have a 6.5 times increased risk of venous thrombosis compared to non-users of hormonal contraception.[2] This is commensurate with the risk of thrombosis due to the use of combination birth control pills, which in studies ranged between 2.9 times to 13.7 times the risk.[3] As such, contraceptive vaginal rings do not necessarily appear to pose a lower risk of thrombosis than do birth control pills.[2][3] A number of lawsuits have been filed alleging the companies involved concealed the health risks associated with using the NuvaRing,[4][5] which are currently being settled for $100 million.[6] In 2016 it was the 214 most prescribed medication in the United States with more than 2 million prescriptions.[7] Medical useThe ring is placed into the vagina for a three-week period, then removal of the ring for one week, during which the user will experience a menstrual period. The break week is comparable to the placebo week for combined oral contraceptive pills ("the Pill"), and the contraceptive effect is maintained during this period. Extended use regimens (seven-week, quarterly, or annual) involving back-to-back use of (2, 4, or 17) rings have been studied in clinical trials, but are not currently approved.[8][9][10] Insertion of the ring is comparable to insertion of other vaginal rings. The muscles of the vagina keep NuvaRing securely in place, even during exercise or sex. Women can check the contraceptive ring periodically with their finger. In rare instances, NuvaRing may fall out during sexual intercourse, while straining before or during a bowel movement, or while removing a tampon.[11][12] In the case of accidental expulsion, the manufacturer recommends rinsing the ring with lukewarm water before reinserting. If not done correctly, the risk of pregnancy is increased. Contraceptive efficacy is reduced if the ring is removed, accidentally expelled, or left outside of the vagina for more than three hours. If left outside of the vagina for more than three hours, the device is to be rinsed and reinserted immediately. If this occurs, the manufacturer recommends that a backup method of contraception be used until the ring has been used continuously for a subsequent seven days.[11][12] BenefitsThe benefits of the ring include:
ContraindicationsThe contraceptive vaginal ring is contraindicated for a risk of blood clots. This is because it contains the hormone etonogestrel, the active metabolite of the prodrug desogestrel. It is a third-generation contraceptive.[4] A study in the BMJ, with over 1.6 million women, found that users of vaginal rings with ethinylestradiol and etonogestrel have a 6.5 times increased risk of venous thrombosis compared to non-users.[2][19] Epidemiological studies have shown that oral contraceptives that contain desogestrel can increase the risk of blood clots (venous thrombosis) by 1.5 to 2.4 times the risk of second-generation oral contraceptives.[20] Second-generation oral contraceptives do not contain desogestrel. Hormones are released continuously from NuvaRing, thus peak and total estrogen and progestin doses are significantly lower than with combined oral contraceptives, but what effect this has on the risk of blood clots has not been established.[12] NuvaRing also has the cardiovascular contraindications associated with combined oral contraceptives, such as stroke and heart attack. These risks have been shown to be much greater if combined with other risk factors such as smoking, recent surgery, a history of cardiovascular disease, or women over 40 years old.[12] NuvaRing should not be used while breastfeeding. The hormones may pass to the baby through the milk, and it may decrease milk production.[21] Side effects[12][22][23] NuvaRing is weight neutral.[24][25] Additional side effect information (including, but not limited to, severe blood clots) is provided in the NuvaRing full prescribing information.[12][23] Breakthrough bleeding occurs in 2.0 to 6.4% of NuvaRing users.[26] Mechanism of actionLike all combined hormonal contraceptives, NuvaRing works primarily by preventing ovulation. A secondary mechanism of action is inhibition of sperm penetration by changes in the cervical mucus. Hormonal contraceptives also have effects on the endometrium that theoretically could affect implantation, however no scientific evidence indicates that prevention of implantation actually results from their use. |