Antiprogestational

Antiprogestational Agents

Antiprogestational agents, also known as antiprogestins, are a class of drugs that inhibit the effects of progesterone, a key hormone in the reproductive system. These agents are primarily used in reproductive health, including contraception, abortion, and the treatment of certain medical conditions such as endometriosis and uterine fibroids.

Mechanism of Action

Antiprogestational agents work by blocking the progesterone receptors in the body. Progesterone is essential for maintaining pregnancy, as it prepares the endometrium for implantation and supports early pregnancy. By inhibiting progesterone, antiprogestins can prevent implantation or disrupt an established pregnancy.

The most well-known antiprogestational agent is mifepristone, which is often used in combination with misoprostol to induce medical abortion. Mifepristone binds to progesterone receptors with high affinity, preventing progesterone from exerting its effects.

Clinical Uses

Contraception

Antiprogestins can be used as emergency contraceptives. By preventing the action of progesterone, they can inhibit ovulation or prevent fertilization and implantation if taken shortly after unprotected intercourse.

Medical Abortion

Mifepristone, in combination with misoprostol, is used to terminate early pregnancies. Mifepristone is administered first to block progesterone, followed by misoprostol to induce uterine contractions and expel the pregnancy.

Treatment of Endometriosis

Endometriosis is a condition where tissue similar to the lining inside the uterus grows outside the uterus, causing pain and infertility. Antiprogestins can help manage symptoms by reducing the growth of endometrial tissue.

Uterine Fibroids

Uterine fibroids are noncancerous growths in the uterus that can cause heavy menstrual bleeding and pain. Antiprogestins can shrink fibroids and alleviate symptoms by reducing the effects of progesterone.

Side Effects

Common side effects of antiprogestational agents include nausea, vomiting, headache, dizziness, and fatigue. Long-term use can lead to changes in menstrual cycles and bone density loss.

Research and Development

Ongoing research is exploring new applications for antiprogestins, including their potential use in treating breast cancer and other hormone-sensitive conditions.

Also see

• Progesterone
• Mifepristone
• Contraception
• Endometriosis
• Uterine fibroids