Also found in: Dictionary, Thesaurus, Encyclopedia.
Related to RU-486: Morning after pill


an antiprogestin used with misoprostol or other prostaglandin to terminate pregnancy in the first trimester; administered orally. Called also RU-486.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

mifepristone (RU-486)

Korlym, Mifegyne (UK), Mifeprex

Pharmacologic class: Synthetic steroid

Therapeutic class: Antiprogestational agent, abortifacient

Pregnancy risk category NR

FDA Box Warning

• Rare cases of serious and sometimes fatal infections and bleeding have followed spontaneous, surgical, and medical abortions, including after mifepristone use. Before starting drug, inform patient of risk of these serious events and discuss medication guide and patient agreement. Ensure that patient knows whom to call and what to do, including going to emergency department (ED) if none of provided contacts are reachable; if she experiences sustained fever, severe abdominal pain, prolonged heavy bleeding, or syncope; or if she has abdominal pain or discomfort or general malaise (including weakness, nausea, vomiting, or diarrhea) more than 24 hours after taking drug.

• Patients with serious bacterial infections and sepsis may present without fever, bacteremia, or significant pelvic examination findings after abortion. Rare deaths have occurred in patients without fever, with or without abdominal pain, but with leukocytosis with marked left shift, tachycardia, hemoconcentration, and general malaise. Maintain high index of suspicion to rule out serious infection and sepsis.

• Advise patient to take medication guide with her if she visits ED or another health care provider who didn't prescribe drug, so provider will be aware that patient is undergoing medical abortion.

• Be aware that pregnancy must be excluded before initiation of treatment with Korlym. Patients must avoid pregnancy during treatment and for 1 month after therapy ends by using a nonhormonal, medically acceptable method of contraception; if patient has had a surgical sterilization, no additional contraception is needed. Pregnancy must also be excluded if treatment is interrupted for more than 14 days in females of childbearing potential.


Antagonizes progesterone receptor sites, inhibiting activity of endogenous and exogenous progesterone and stimulating uterine contractions, which causes fetus to separate from placental wall


Tablets: 200 mg, 300 mg

Indications and dosages

Termination of intrauterine pregnancy through day 49 of pregnancy

Adults: On day 1, mifepristone 600 mg P.O. as a single dose. On day 3, misoprostol 400 mcg P.O. (unless abortion has been confirmed).

Hyperglycemia secondary to hypercortisolism in adults with endogenous Cushing's syndrome who have type 2 diabetes or glucose intolerance and have failed surgery or aren't candidates for surgery

Adults: Initially, 300 mg P.O. daily; increase based on clinical response and tolerability in 300-mg increments to a maximum of 1,200 mg daily. Don't exceed 20 mg/kg/day.

Dosage Adjustment

• Renal impairment (Korlym)

• Mild to moderate hepatic impairment (Korlym)

• Concurrent use of strong P450 CYP3A inhibitors (Korlym)


• Hypersensitivity to drug, misoprostol, or other prostaglandins

• Confirmed or suspected ectopic pregnancy or adnexal mass

• Chronic adrenal failure

• Bleeding disorders

• Concurrent anticoagulant therapy or long-term corticosteroid therapy

• Presence of intrauterine device (IUD)

• Inherited porphyrias

• Concomitant treatment with systemic corticosteroids for serious medical conditions or illnesses (Korlym)

• Concurrent use of simvastatin or lovastatin and CYP3A substrates with narrow therapeutic range (Korlym)

• History of unexplained vaginal bleeding or endometrial hyperplasia with atypia or endometrial carcinoma (Korlym)

• Pregnancy (Korlym)


Use cautiously in:

• cardiovascular, respiratory, renal, or hepatic disorders; hypertension; type 1 diabetes mellitus; anemia; jaundice; seizure disorder; cervicitis; infected endocervical lesions; acute vaginitis; uterine scarring

• hypokalemia, underlying heart conditions including heart failure and coronary vascular disease (Korlym)

• hemorrhagic disorders or concurrent use of anticoagulants (Korlym)

• concurrent use of QT interval-prolonging drugs, patients with potassium channel variants resulting in long QT interval (avoid Korlym use)

• concurrent use of drugs metabolized by CYP2B6 and moderate CYP3A inhibitors (Korlym)

• concurrent use of CYP3A inducers (such as rifampin, rifabutin, rifapentin, phenobarbital, phenytoin, carbamazepine, and St. John's wort) or hormonal contraceptives (avoid use)

• concurrent use of strong CYP3A inhibitors (use Korlym with extreme caution and only when necessary; limit dosage to 300 mg)

• concurrent use of drugs metabolized by CYP2C8/2C9 (use lowest dose of CYP2C8/2C9 substrates when used with Korlym)

• breastfeeding patients (Korlym)

• children (Korlym; safety and efficacy not established).


• Before giving dose for termination of pregnancy, make sure patient doesn't have an IUD in place.

• Correct hypokalemia before starting Korlym.

• Give for termination of pregnancy only in health care facility under supervision of health care provider qualified to assess pregnancy stage and rule out ectopic pregnancy.

• Administer with fluids, but not with grapefruit juice.

• When giving for termination of pregnancy, confirm pregnancy termination 14 days after initial dose.

Adverse reactions

CNS: dizziness, fainting, headache, weakness, fatigue, insomnia, asthenia, anxiety, syncope, rigors

CV: hypertension, QT-interval prolongation (Korlym)

EENT: sinusitis

GI: nausea, vomiting, diarrhea, abdominal cramping, dyspepsia

GU: vaginitis, leukorrhea, uterine cramping, pelvic pain; endometrial hypertrophy, cystic dilatation of endometrial glands, vaginal bleeding (Korlym); uterine hemorrhage

Hematologic: anemia

Metabolic: hypokalemia, adrenal insufficiency (Korlym)

Musculoskeletal: leg pain, back pain, arthralgia

Skin: rash (Korlym)

Other: viral infections; fever, decreased appetite, peripheral edema, opportunistic infections (Korlym)


Drug-drug. CYP2C8/2C9 substrates: increased plasma concentrations of these drugs

CYP3A inducers (such as carbamazepine, phenobarbital, phenytoin, rifabutin, rifampin, rifapentin): decreased mifepristone concentrations

CYP3A substrates with narrow therapeutic range (such as cyclosporine, dihydroergotamine, ergotamine, fentanyl, pimozide, quinidine, sirolimus, tacrolimus): increased exposure of these drugs and effects

Drugs metabolized by CYP2B6 (bupropion, efavirenz): significantly increased exposure of these drugs

Drugs metabolized by CYP3A (lovastatin, simvastatin): increased risk of myopathy and rhabdomyolysis

Glucocorticoids: antagonized glucocorticoid effect

Moderate CYP3A inhibitors (such as amprenavir, aprepitant, atazanavir, ciprofloxacin, darunavir/ritonavir, diltiazem, erythromycin, fluconazole, imatinib, verapamil), strong CYP3A inhibitors (such as amprenavir, boceprevir, clarithromycin, conivaptan, fosamprenavir, indinavir, itraconazole, lopinavir, mibefradil, nefazodone, nelfinavir, posaconazole, ritonavir, saquinavir, telaprevir, telithromycin, voriconazole): increased plasma mifepristone concentration

Oral contraceptives: decreased oral contraceptive effectiveness

Drug-diagnostic tests. Hematocrit, hemoglobin: decreased values

Potassium: decreased level

Red blood cells: decreased count

Drug-food. Grapefruit juice: increased mifepristone blood level and effects

Drug-herbs. St. John's wort: decreased mifepristone blood level and effects

Patient monitoring

• Assess vital signs, breath sounds, and bowel sounds.

• Monitor uterine contractions and type and amount of vaginal bleeding.

• Evaluate CBC.

• Monitor serum potassium level 1 to 2 weeks after starting or increasing Korlym dosage and periodically thereafter.

Closely monitor patient taking Korlym for signs and symptoms of adrenal insufficiency, including weakness, nausea, increased fatigue, hypotension, and hypoglycemia. If adrenal insufficiency is suspected, discontinue drug immediately and administer glucocorticoids without delay. May resume Korlym at a lower dosage after resolution of adrenal insufficiency.

• Be aware that patients with endogenous Cushing's syndrome are at risk for opportunistic infections such as Pneumocystis jiroveci pneumonia while taking Korlym. Monitor patient for respiratory distress shortly after Korlym initiation. Initiate appropriate diagnostic tests and treat P. jiroveci as indicated.

Patient teaching

When used for termination of pregnancy:

• After administration, tell patient she will need to return in 48 hours for a prostaglandin drug or to verify pregnancy termination.

• Tell patient she will have contractions for 3 or more hours after receiving drug and that vaginal bleeding may last 9 to 16 days.

Instruct patient to contact prescriber if she has persistent or extremely heavy vaginal bleeding, extreme fatigue, or orthostatic hypotension.

Caution patient that vaginal bleeding does not prove that complete abortion has occurred. Tell her she will need follow-up appointment 2 weeks later to verify pregnancy termination.

• Inform patient that she is at risk for pregnancy right after abortion is complete. Encourage appropriate contraceptive decision.

When used for hyperglycemia secondary to hypercortisolism in patients with endogenous Cushing's syndrome:

Instruct patient to recognize and report signs and symptoms of hypokalemia, respiratory infections, and adrenal insufficiency.

• Advise patient not to take drug with grapefruit juice and not to use herbal products without consulting prescriber.

When used for either indication:

• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, foods, and herbs mentioned above.

McGraw-Hill Nurse's Drug Handbook, 7th Ed. Copyright © 2013 by The McGraw-Hill Companies, Inc. All rights reserved


Synthetic chemical compound with antiprogesterone properties used for early pregnancy termination; the substance binds with glucocorticoid receptors resulting in increased adrenal gland secretion.
Synonym(s): RU-486
Farlex Partner Medical Dictionary © Farlex 2012


Abbreviation for mifepristone.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
References in periodicals archive ?
(81) While it may be understandable that not all physicians and pharmacists (let alone patients) keep current with the continuing debate regarding the hostile endometrium theory, studies have shown that many physicians, pharmacists, and nurses mistakenly believe that EC is the same thing as RU-486 or, at least, that it works in the same way.
In 2002, Cytotec was relabeled to emphasize that "patients must be advised of the abortifacient property and warned not to give the drag to others." The FDA has endorsed its use with RU-486 and recognizes its off-label use by obstetricians to induce contractions in routine deliveries, a practice that remains controversial due to the risk of serious hemorrhaging in the mother and harm to the baby.
Just as the right-wing doesn't want Plan B and RU-486 available to women because they believe it promotes promiscuous sexuality and abortion, they don't want the HPV vaccine given to girls because they believe it will promote sexual promiscuity in teenagers.
Doctors say heavy bleeding is a normal side effect when using RU-486, and blood clots and strokes are known risks for using the patch, says Dr.
The events surrounding RU-486 offer one illustration.
How to avoid a pregnancy should be the top priority of the pro-choice education package, which should give young people an escalating list of choices--no sex, sex using condoms, sex using birth control like the Pill, the morning-after pill, RU-486 and, last, a surgical procedure.
We expect to report later on many of the following: PA-457, SPD-754, GW873140, GW678248, SN1212/1461, TMC114, TNX-355, PRO140, UK-427,857, AK602, KRH-2731, mifepristone (RU-486), and chloroquine.
The lobbyists, who crafted Sheldon's argument, hired him to argue that allowing importation of these drugs could lead to the legalization of RU-486, the so-called "abortion pill." The stunt backfired because the bill is popular among many lawmakers, including several conservative Republicans.
(1.) Gellene D, RU-486 abortion pill hasn't caught on in U.S.; physicians have stayed away from medication and clinics are noncommittal, Los Angeles Times, May 31, 2001, p.
State Department announced that the United States may withdraw its pledged $3 million for a World Health Organization reproductive health program that includes research on RU-486, the so-called "abortion pill."
Holland's Minister of Health has authorized the activists of Women on Waves to provide the RU-486 pill (Mifepristone) to women in countries where the voluntary termination of pregnancy is prohibited.
ONE YEAR AFTER the Food and Drug Administration (FDA) approved the abortion pill Mifeprix, better known as RU-486, the Kaiser Family Foundation has released numbers regarding its actual availability to American women.