Abortifacients mifepristone

Mifepristone [RU 486] (Mifeprex) [Abortifacient/Synthetic Steroid] WARNING Pt counseling information required associated w/... 

Mifepristone, an antagonist at progesterone and glucocorticoid receptors, has a luteolytic effect and is effective as a postcoital contraceptive. When combined with a prostaglandin it is also an effective abortifacient. 

ZK 98734 (lilopristone) is a potent experimental progesterone inhibitor and abortifacient in doses of 25 mg twice daily. Like mifepristone, it also appears to have antiglucocorticoid activity. 

Misoprostol, an analogue of PGE1 is licensed for use in the management of gastroduodenal ulceration. It is an effective myometrial stimulant of the pregnant uterus and is used for the induction of labor and as abortifacient, both alone and in combination with other substances (for example mifepristone). It provides an effective alternative to gemeprost, the most widely used prostaglandin pessaries in combination with mifepristone. 

The antiprogesterone mifepristone, almost exclusively used as an abortifacient, has also been tried as a post-coital contraceptive (11). In one randomized... 

Controversy surrounding the use of mifepristone as an abortifacient has continued, particularly in the USA. Many of the objections raised reflect ethical or religious views, but various papers have stressed the risks involved, such as the fact that in the USA at least two preventable deaths have occurred, as well as other life-threatening complications. It has also been argued that approval of mifepristone as an abortifacient breached the FDA s procedural rules. In 2002 a Citizen Petition to the Congress called for a revocation of the drug s approval (4). 

The antiprogesterone mifepristone, almost exclusively used as an abortifacient, has also been tried as a post-coital contraceptive (11). In one randomized comparative trial, a single dose of mifepristone 600 mg was at least as effective as the usual hormonal method (12). Women who took mifepristone had lower rates of adverse effects, particularly nausea and vomiting, but their next menstrual period was more likely to be delayed. In another randomized trial, both methods were equally effective (SEDA-16, 466). The use of an estrogen + a progestogen had a higher total incidence... 

Competitive progesterone receptor antagonists are available, and one such, mifepristone, is used to procure therapeutic abortion see ABORTIFACIENTS. 

Structures of steroids used as oral contraceptives. (A) Combination pills containing an estrogen -P progestin. (B) The progestin-only pill. (C) RU-486 or mifepristone, which can be utilized as an abortifacient. [Reproduced with permission from S. W. Norman and G. Litwack, Hormones, 2nd ed. San Diego Academic Press, 1997]. 

Uterine smooth muscle contraction — either misoprostol (PGEj analog) or dinoprostone can be used for cervical ripening and as abortifacient (in conjunction with mifepristone, RU486). 

Uterine and bronchiolar smooth muscle contraction —> dinoprost and carboprost are used as abortifacients with mifepristone. 

Significant side effects are those associated with its abortifacient properties and other smooth muscle contraction effects, e.g., diarrhea and abdominal pain. Misoprostol also is an effective cervical ripening agent (by vaginal application) for the induction of labor. Other unlabeled uses include the treatment of postpartum hemorrhage and, with mifepristone, termination of pregnancy. 

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