Mifepristone

Indications

Mifepristone is used for: Termination of pregnancy, Labour induction, Cervical softening and dilatation, Postcoital contraception.

Adult Dose

Pregnancy Termination Mifepristone: Indicated for the medical termination of intrauterine pregnancy through 70 days gestation in combination with misoprostol Day 1: 200 mg of mifepristone PO as a single dose under physician supervision Days 2-3: 800 mcg of MISOPROSTOL buccally once as a single dose; must be administered a minimum of 24-hr and a maximum of 48-hr following mifeprostone dose on day 1 Days 7-14 Must return for follow-up visit to confirm complete termination has occurred by medical history, clinical examination, hCG testing, or ultrasonographic scan If complete expulsion has not occurred, but the pregnancy is not ongoing, women may be treated with another dose of misoprostol 800 mcg buccally with follow-up in ~7 days Lack of bleeding following treatment usually indicates failure; however, prolonged or heavy bleeding is not proof of a complete abortion Surgical evacuation is recommended to manage ongoing pregnancies after medical abortion

Child Dose

Renal Dose

Administration

May be taken with or without food. 200 mg PO once given by a healthcare provider in a clinic, medical office, or hospital followed 24-48 hr later by misoprostol buccal administration Buccal administration (misoprostol) Because most women will expel the pregnancy within 2-24 hr of taking misoprostol, discuss with the patient an appropriate location for her to be when she takes the misoprostol, taking into account that expulsion could begin within 2 hr of administration Administer misoprostol 800 mcg buccally within 24-48 hr after taking Mifeprex The effectiveness of the regimen may be lower if misoprostol is administered <24 hr or >48 hr after mifepristone administration Tell the patient to place two 200 mcg misoprostol tablets in each cheek pouch (the area between the cheek and gums) for 30 minutes and then swallow any remnants with water or another liquid During the period immediately following the administration of misoprostol, the patient may need medication for cramps or GI symptoms

Contra Indications

Confirmed or suspected ectopic pregnancy, chronic adrenal failure, concurrent long-term corticosteroid therapy, history of allergy to mifepristone, misoprostol or other prostaglandin, haemorrhagic disorders or concurrent anticoagulant therapy, porphyria, hepatic or renal impairment; pregnancy and lactation; IUD in place; undiagnosed adnexal mass.

Precautions

Patient w/ haemostatic disorders or anaemia; malnutrition. Patients taking strong CYP3A4 inhibitors (when used in the treatment of Cushing's syndrome). Hepatic and renal impairment. Lactation. Monitoring Parameters Termination of pregnancy: Monitor Hb, haematocrit and RBC count in cases of heavy bleeding; CBC in patients who show signs of infection. Conduct clinical exam and/or ultrasound to confirm complete termination of pregnancy. Cushing's syndrome: Monitor thyroid function, serum glucose, psychiatric symptoms, signs/symptoms of adrenal insufficiency; cushingoid appearance. Lactation Distributed in human milk; because of the potential for serious adverse reactions in nursing infants from mifepristone, a decision should be made whether to discontinue nursing or to discontinue the drug, taking into account the importance of the drug to the mother

Pregnancy-Lactation

Pregnancy Drug contraindicated in pregnancy because use results in pregnancy loss; there are no data that assess risk of birth defects in women exposed to drug during pregnancy Available data limited to exposure following a single dose of mifepristone during pregnancy showed a higher rate of major birth defects compared to the general population comparator Pregnancy testing Due to its anti-presentational activity, drug causes pregnancy loss; perform pregnancy testing before initiation of treatment or if treatment interrupted for more than 14 days in females of reproductive potential Contraception Recommend non-hormonal contraception for duration of treatment and for one month after stopping treatment; drug interferes with effectiveness of hormonal contraceptives Lactation Drug is present in human milk, however, there are no data on amount of mifepristone in human milk, effects on breastfed infant, or on milk production during long term use of mifepristone; developmental and health benefits of breastfeeding should be considered along with mother’s clinical need for Korlym and any potential adverse effects on breastfed child from drug or from the underlying maternal condition To minimize exposure to a breastfed infant, women who discontinue or interrupt treatment may consider pumping and discarding milk during treatment and for 18-21 days (5-6 half-lives) after last dose, before breastfeeding

Interactions

Increased serum levels w/ CYP3A4 inhibitors (e.g. ketoconazole, itraconazole, erythromycin). Decreased serum levels w/ CYP3A4 inducers (e.g. dexamethasone, rifampicin, phenytoin). Potentially Fatal: Increased risk of adverse effects w/ simvastatin, lovastatin and CYP3A4 substrates w/ narrow therapeutic range (e.g. ciclosporin, pimozide, ergotamine). Antagonises the effect of glucocorticoids. Increased risk of vag bleeding w/ anticoagulants.

Adverse Effects

Side effects of Mifepristone : >10% Abdominal pain, cramping (96%), Uterine cramping (83%), Nausea (43-61%), Headache (2-31%), Vomiting (1-26%), Diarrhea (12-20%), Dizziness (1-12%) 1-10% (Mifeprex) Fatigue (10%), Back pain (9%), Decreased hemoglobin >2 g/dL (6%), Uterine hemorrhage (5%), Viral infection (4%).Dyspepsia (3%), Insomnia (3%), Rigors (3%), Vaginitis (3%), Anemia (2%), Anxiety (2%), Fainting (2%), Leg pain (2%), Leukorrhea (2%), Pelvic pain (2%), Sinusitis (2%), Weakness (2%)

Mechanism of Action

Mifepristone is a progesterone antagonist with antiglucocorticoid activity. It binds to the intracellular progesterone receptor where it competitively inhibits progesterone attachment. It is also a partial progesterone agonist.