It is a progestin antagonist indicated, in a regimen with misoprostol, for the medical termination of intrauterine pregnancy through 70 days gestation
Drugs acting on the Uterus
Mifepristone is an antiprogestin; that is, it blocks the action of progesterone, a naturally produced hormone that prepares the inner lining of the uterus for implantation of a fertilized ovum and support of a growing embryo and placenta. The drug is taken orally in a prescribed dose during the first seven to nine weeks of pregnancy, and within two days the uterine lining begins to deteriorate, usually causing bleeding similar to that experienced during normal menstruation. The Mifepristone is then followed up by a dose (taken orally or as a vaginal suppository) of the synthetic prostaglandin Misoprostol, which stimulates the uterus to undergo contractions. The embryo and other uterine contents are expelled in a process very similar to spontaneous abortion or miscarriage.
200 mg on Day 1, followed 24-48 hours after it dosing by 800 mcg buccal misoprostol. ? Instruct the patient what to do if significant adverse reactions occur. ? Follow-up is needed to confirm complete termination of pregnancy.
ketoconazole, itraconazole, erythromycin and grapefruit juice may inhibit its metabolism (increasing serum levels of mifepristone). Furthermore, rifampicin, dexamethasone, St John's Wort and certain anticonvulsants (phenytoin, phenobarbital, carbamazepine) may induce mifepristone metabolism (lowering serum levels of Mifepristone). Based on invitro inhibition information, co-administration of mifepristone may lead to an increase in serum levels of drugs that are CYP3A4 substrates.
Limited evidence suggests that co-administration of NSAIDs on the day of prostaglandin administration does not adversely influence the effects of Mifepristone or the prostaglandin on cervical ripening or uterine contractility and does not reduce the clinical efficacy of medical termination of pregnancy.
Confirmed/suspected ectopic pregnancy or undiagnosed adnexal mass ? Chronic adrenal failure ? Concurrent long-term corticosteroid therapy ? History of allergy to mifepristone, misoprostol, or other prostaglandins ? Hemorrhagic disorders or concurrent anticoagulant therapy ? Inherited porphyria ? Intrauterine device (IUD) in place
Nausea, weakness, fever/chills, vomiting, headache, diarrhea, and dizziness
Pregnancy: Risk of fetal malformations in ongoing pregnancy if not terminated is unknown actation: It is not known whether Mifepristone is excreted in human milk. Many hormones with a similar chemical structure, however, are excreted in breast milk. Since the effects of Mifepristone on infants are unknown, breast-feeding women should consult with their health care provider to decide if they should discard their breast milk for a few days following administration of the medications.
Single doses of Mifepristone up to 2 gm caused no unwanted reaction. In the event of massive ingestion, signs of adrenal failure might occur. Acute intoxication may require admission to hospital and if relevant treatment with dexamethasone.
Store in a cool and dry place, protected from light, store below 25°C.
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