Blog
Mifepristone and Misoprostol: What You Need to Know About Their Uses
Mifepristone
Mifepristone is taken orally and works by blocking progesterone, which is crucial for maintaining a pregnancy. When taken in combination with misoprostol, it is highly effective in terminating early pregnancies. This medication is also beneficial for non-pregnancy-related conditions, such as managing Cushing’s syndrome, a condition where the body produces too much cortisol, and endometriosis, where tissue similar to the uterine lining grows outside the uterus. It may also be prescribed for fibroids or certain types of cancer.
Misoprostol
Misoprostol, administered in different ways (oral, buccal, or vaginal), primarily works by inducing uterine contractions. This medication is crucial in the process of medical abortion, as it helps expel the contents of the uterus after mifepristone has made it inhospitable for pregnancy to continue. It also has vital roles in preventing and healing ulcers, especially for patients using NSAIDs, and managing labor or excessive bleeding after childbirth.
Mifepristone Vs Misoprostol
| Aspect | Mifepristone | Misoprostol |
|---|---|---|
| Primary Use | Mifepristone is primarily used in medical abortion for early pregnancies (within 10 weeks) in combination with misoprostol. It prevents pregnancy continuation by blocking the hormone progesterone, which is essential for maintaining pregnancy. | Misoprostol is used to induce uterine contractions. It is commonly used in combination with mifepristone for medical abortion, but also for labor induction, managing postpartum bleeding, and preventing or treating gastric ulcers. |
| Mechanism of Action | Mifepristone works by blocking progesterone, a hormone that is vital for sustaining pregnancy. This makes the uterine lining unstable and prevents the embryo from continuing its development, leading to pregnancy termination. | Misoprostol mimics prostaglandins, causing the uterus to contract. It helps expel pregnancy tissue in abortion, induces labor by stimulating contractions, and can also help prevent stomach ulcers by protecting the stomach lining. |
| Common Dosage | The typical dosage for medical abortion is 200 mg taken orally as a single dose. For other uses like Cushing’s syndrome, it may vary. In clinical practices, mifepristone is often followed by a dose of misoprostol. | The usual dosage for medical abortion ranges from 400 mcg to 800 mcg, administered orally, buccally, or vaginally, depending on the medical indication. For labor induction, the dosage and route vary based on the gestational age and patient condition. |
| Route of Administration | Mifepristone is most commonly administered orally as a single tablet. It is typically prescribed for use in a clinical setting, under medical supervision, especially when used for abortion or other hormonal treatments. | Misoprostol can be administered in several ways: orally (swallowed), buccally (dissolved in the cheek), or vaginally (inserted into the vagina). The route is determined based on the medical condition being treated, such as abortion or ulcer prevention. |
| Use in Pregnancy | Mifepristone is used specifically for medical abortion in the early stages of pregnancy (up to 10 weeks). It is also effective for preventing pregnancy continuation when combined with misoprostol. | Misoprostol is often used after mifepristone to complete a medical abortion, facilitating the expulsion of the pregnancy tissue from the uterus. It is also used for labor induction and managing postpartum hemorrhage. |
| Other Medical Applications | Mifepristone has additional applications, including the treatment of Cushing’s syndrome, endometriosis, uterine fibroids, and certain cancers. It is used off-label for conditions that involve excess glucocorticoid production. | Misoprostol is used in non-pregnancy-related treatments, such as preventing and healing stomach ulcers caused by nonsteroidal anti-inflammatory drugs (NSAIDs). It is also used for inducing labor or managing bleeding after childbirth (postpartum hemorrhage). |
| Side Effects | Common side effects include nausea, vomiting, fatigue, abdominal pain, cramping, and vaginal bleeding. These effects are often temporary and related to the medication’s role in inducing the termination of pregnancy. | Misoprostol’s side effects include diarrhea, abdominal cramping, nausea, fever, chills, headache, and dizziness. These effects are more pronounced when the medication is used for abortion, especially in higher doses. |
| Contraindications | Mifepristone is contraindicated in individuals with known or suspected ectopic pregnancy, hypersensitivity to the drug, or pregnancy beyond 10 weeks. It should not be used in cases where there is heavy bleeding or in individuals with certain conditions like adrenal failure. | Misoprostol is contraindicated in individuals with a known hypersensitivity to the drug. Caution should be exercised in people with a history of heart disease, uterine scarring, or other uterine conditions. |
| Duration of Action | The effects of mifepristone are typically seen within a few hours after administration. For abortion, its action is enhanced when followed by the administration of misoprostol, with the entire process taking a few days to complete. | Misoprostol’s effects typically begin within 4-6 hours after administration, and they can last for a few hours, depending on the dose and the intended use. For medical abortion, its primary action is to expel the pregnancy tissue, and for ulcers, its effect is protective over a longer period. |
| Effectiveness | Mifepristone is highly effective for medical abortion, with success rates exceeding 98% when used in combination with misoprostol. It is also effective in treating conditions like Cushing’s syndrome, where it helps regulate cortisol levels. | Misoprostol is highly effective when used for its intended purposes, such as inducing abortion in combination with mifepristone or managing postpartum bleeding. It is also used to prevent ulcers, with high success rates, especially when used alongside NSAIDs. |
| Legal Status | Mifepristone is typically available by prescription and is regulated in many countries for medical abortion purposes. It is often prescribed in a clinical setting where the procedure is monitored by a healthcare provider. | Misoprostol is available by prescription, and it is often prescribed alongside mifepristone for medical abortion. Its uses in labor induction, ulcer treatment, and other off-label uses are also regulated by prescription. |
| Storage | Mifepristone should be stored at room temperature, away from moisture and heat. It is typically stored in its original packaging until use. | Misoprostol should be stored at room temperature, away from moisture and heat, to maintain its effectiveness. It should be kept in its original packaging until use to ensure proper storage conditions. |
Frequently Asked Questions
What Is the Difference Between Mifepristone and Misoprostol?
-
Mifepristone blocks the hormone progesterone, which is necessary for pregnancy to continue. It detaches the embryo from the uterine lining.
-
Misoprostol induces uterine contractions and softens the cervix to expel pregnancy tissue.
Which Combination Is More Effective?
The combination of mifepristone and misoprostol is more effective than misoprostol alone. For early pregnancy loss, success rates are approximately 95–98% up to 63 days of gestation. Using misoprostol alone yields success rates between 67% and 70%.
How Are They Taken?
-
Mifepristone: Taken orally as a single dose.
-
Misoprostol: Administered 24–48 hours later, either buccally (between the cheek and gum), vaginally, or sublingually.
What Are the Side Effects?
-
Mifepristone: Common side effects include nausea, vomiting, and abdominal pain.
-
Misoprostol: May cause diarrhea, abdominal pain, and uterine cramps.
Both medications are generally well-tolerated, with serious complications being rare.
How Safe Are They?
Both mifepristone and misoprostol have been used safely in medical abortions for over two decades. Serious adverse events are uncommon, and the combination regimen is endorsed by major medical organizations, including the American College of Obstetricians and Gynecologists and the World Health Organization.
Up to How Many Weeks Can They Be Used?
-
Mifepristone and Misoprostol Combination: Approved and effective for medical abortion up to 77 days (11 weeks) of gestation .
-
Misoprostol Alone: Can be used up to 12 weeks of gestation, but effectiveness is lower compared to the combination regimen.