February 08, 2010
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The Three M's of Medical Abortion — Mifepristone, Methotrexate and Misoprostol
While there are now several medical abortion drugs, as well as different ways of administering them, all of the approaches have one thing in common: they make use of one or more of three drugs: mifepristone, methotrexate and misoprostol. The Three Medical Abortion Drugs
Mifepristone, A.K.A. RU-486
Around the year 1980, researchers at the French company, Roussel Uclaf, discovered a drug that interferes with the body's ability to utilize the hormone progesterone. They called it RU (for Roussel Uclaf) 486.
Progesterone is a key player in the body's early preparations for pregnancy, helping to prepare the wall of the uterus for the implantation of the embryo, or rapidly dividing fertilized egg. If the body does not provide sufficient amounts of progesterone, the embryo cannot be implanted in the uterus. When this occurs, the uterus expels the embryo by a series of muscular contractions and the pregnancy is terminated. As they investigated the use of mifepristone as an abortion drug, early researchers found that the drug's success rate in causing abortion was no better than 80%. But when they combined mifepristone with other drugs, such as misoprostol that further stimulate uterine contractions, the success rate rose to almost 90%. This combination, a technique which is called the "French Protocol," has been widely and successfully used in France, Sweden, China and the United States.(1)(2) The dose of mifepristone used in the French Protocol is 600 mg. Recent studies, however, have suggested that much lower doses can be just as effective and may be safer. In the U.S., the most common protocols are two variations on the French Protocol called the Population Council, or PC, Protocol and the Abortion Rights Movement, or ARM, Protocol. These are named for two large-scale studies of medical abortion that were done in the United States. A key benefit of these protocols is that they can be done very early in pregnancy. This is also an important limitation because medical abortion drugs do not work as well after the seventh week of pregnancy when other hormones and mechanisms, including the growth of the placenta (the organ formed in the uterus during pregnancy), support the pregnancy. The seventh week is up to the 49th day after the first day of the last menstrual period.(3) Methotrexate
Methotrexate is not new; it was approved as an anticancer drug in the U.S. in 1953. It has also been used in treating other diseases, including rheumatoid arthritis and psoriasis. Methotrexate works by interfering with the development of rapidly dividing cells in the human body.
In 1982, researchers discovered that methotrexate was an effective treatment for ectopic pregnancy. Ectopic pregnancy is a dangerous condition in which a fertilized human egg implants in the wrong place, usually in one of the two fallopian tubes that transport eggs from the ovaries to the uterus. While an ectopic pregnancy cannot produce a baby, it can threaten the health, fertility and even the life of the woman. Before methetrexate, the only treatment for an ectopic pregnancy was surgery. The surgery, unfortunately, often results in fertility problems because the fallopian tube, sometimes also an ovary or, in the worst cases, the entire uterus may need to be removed. Methotrexate doesn't interfere with progesterone but, instead, prevents the growth of the rapidly dividing cells of the developing placenta. The drug has proven to have the same effect on normal pregnancies in the uterus. Once researchers saw the potential of methotrexate as a medical abortion drug, they tried it in combination with misoprostol, usually given as a vaginal suppository. They found that the methotrexate/misoprotol combination had a 90% success rate, which was comparable to that achieved with mifepristone/misopristol.(4) Misoprostol
Misoprostol is a drug with many uses; for one, it is given to people who are taking certain anti-inflammatory drugs in order to prevent stomach ulcers. Because it can also cause uterine contractions, it has become a second component of medical abortion along with either methotrexate or mifepristone.
In the French Protocol, misoprostol is given in pill form (400 mcg) 48 hours after a woman has taken mifepristone. It is sometimes prescribed as a vaginal suppository (800 mcg) because this route can be safer and more effective, especially with pregnancies that are farther along.5 The use of misoprostol by itself for medical abortion has been studied, particularly in Brazil, where abortion is illegal and misoprostol is the easiest of the three medical abortion drugs to acquire. These studies have found that although misoprostol is about as effective as both two-drug combinations, there are many more unpleasant side effects.(4)(6)
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Comment by: melissataylor1977@yahoo.com
Sat., Feb. 6, 2010 at 1:00 am EST i am 14wks and i just found out the baby has swelling of the brain and spine possibly a sign of down-syndrome. am i too late to terminate my pregnacy by using the pill or anything other than the surgical procedure? thank you for any information you can provide for me |
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