How do receptor modulator progestins work?
Receptor modulator progestins are a class of medications known as selective progesterone receptor modulators (SPRMs). SPRMs are used for emergency contraception after unprotected vaginal intercourse or known or suspected failure of another contraceptive method.
Receptor modulator progestins primarily prevent pregnancy by delaying follicular rupture and ovulation, if taken before ovulation occurs. The medication’s efficacy in preventing pregnancy after ovulation has occurred is thought to be because it may alter the endometrial tissue making it inhospitable and unsuitable for implantation.
Receptor modulator progestins work by modulating the activity of progesterone receptors, which are proteins activated by progesterone, found mainly in female reproductive tissue and some other types of tissue. Progesterone plays a vital role in the regulation of menstruation, ovulation, implantation, and maintenance of pregnancy.
Receptor modulator progestins bind to progesterone receptors in the ovary and prevent natural progesterone from stimulating follicular rupture and release of the mature egg. In the uterus, it interferes with progesterone’s functions in preparing the endometrium for implantation of the fertilized egg.
How are progestin receptor modulators used?
Progestin receptor modulators are single-dose oral tablets approved by the FDA to prevent pregnancy in adult women after unprotected vaginal intercourse or a known or suspected failure of another contraceptive method.
- Progestin receptor modulators must be taken as early as possible within 120 hours of intercourse to be effective.
- They have a higher efficacy when taken within 72 hours of intercourse.
What are the side effects of progestin receptor modulators?
Side effects of progestin receptor modulators may include the following:
- Menstruation delayed by seven or more days than expected
- Abdominal and upper abdominal pain
- Dysmenorrhea (painful menstruation)
- Intermenstrual bleeding
Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with travel medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.