What are the emergency contraceptive pills?
Jun 20, 2025
Source: Cainiu Health
Dr. Zhang Lu
Introduction
Common emergency contraceptive drugs include Levonorgestrel Tablets, Levonorgestrel Enteric-coated Tablets, Levonorgestrel Capsules, Mifepristone Tablets, and Compound Levonorgestrel Tablets. These medications primarily work by inhibiting ovulation and preventing implantation of a fertilized egg. They should typically be taken within 72 hours after unprotected sexual intercourse or contraceptive failure. It should be noted that emergency contraception is a remedial measure and cannot replace regular contraceptive methods.
Emergency contraceptive pills generally include Levonorgestrel tablets, Levonorgestrel enteric-coated tablets, Levonorgestrel capsules, Mifepristone tablets, and Compound Levonorgestrel tablets. It is recommended to use these medications under a doctor's guidance. Detailed explanations are as follows:
1. Levonorgestrel Tablets: A commonly used emergency contraceptive pill, with Levonorgestrel as its main ingredient. It works by inhibiting ovulation, preventing implantation of the fertilized egg, increasing the viscosity of cervical mucus, and enhancing resistance to sperm penetration, thereby achieving emergency contraception. It should be taken within 72 hours after unprotected sex or contraceptive failure; the earlier it is taken, the better the pregnancy prevention effect.
2. Levonorgestrel Enteric-coated Tablets: The active ingredient is also Levonorgestrel, but this formulation uses enteric-coating technology. This formulation dissolves and is absorbed only after reaching the intestine, reducing irritation to the gastric mucosa and lowering the likelihood of gastrointestinal adverse reactions such as nausea and vomiting. The method of administration is to take one tablet within 72 hours after intercourse. If vomiting occurs within 2 hours after taking the medication, another tablet should be taken immediately.
3. Levonorgestrel Capsules: A capsule formulation containing Levonorgestrel as its core ingredient. It effectively inhibits ovulation, prevents implantation of the fertilized egg, and alters the morphology and function of the endometrium, interfering with implantation. It should be taken orally once within 72 hours after unprotected sex or contraceptive failure, with one capsule taken at a time.
4. Mifepristone Tablets: Not a simple progestin-type emergency contraceptive pill, Mifepristone is an antiprogestin medication at the receptor level. It can terminate early pregnancy, prevent implantation, induce menstruation, and promote cervical ripening. When used for emergency contraception, take 25 mg orally on an empty stomach or two hours after eating within 72 hours after unprotected sex, and avoid eating for 1-2 hours afterward.
5. Compound Levonorgestrel Tablets: A compound preparation composed of Levonorgestrel and Ethinyl Estradiol. Levonorgestrel inhibits ovulation, while Ethinyl Estradiol increases the viscosity of cervical mucus, hindering sperm penetration. Combined use enhances the contraceptive effect. It should be taken as soon as possible within 72 hours after unprotected sex—the earlier it is taken, the better the effect in preventing pregnancy. Take two tablets at once, or take one tablet first and then take the second tablet 12 hours later.
Emergency contraception is only a post-coital backup measure and should not replace regular contraceptive methods. Frequent use of emergency contraceptive pills may cause adverse effects such as menstrual disorders and endocrine dysfunction. If there is no plan for pregnancy, it is recommended to practice regular contraceptive measures daily to reduce the risk of unintended pregnancy.
