RU-486

RU-486 mifepristone.

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RU-486.

See mifepristone.

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mifepristone [mĭf″ĕ-pris´tōn]

an antiprogestin used with misoprostol or other prostaglandin to terminate pregnancy in the first trimester; administered orally. Called also RU-486.

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mifepristone (RU-486) Warning - Hazardous drug!

Mifegyne (UK), Mifeprex

Pharmacologic class: Synthetic steroid

Therapeutic class: Antiprogestational agent, abortifacient

Pregnancy risk category NR

FDA Boxed 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 healthcare provider who didn't prescribe drug, so provider will be aware that patient is undergoing medical abortion.

Action

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

Availability

Tablets: 200 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).

Contraindications

• 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

Precautions

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.

Administration

• Before giving, make sure patient doesn't have an IUD in place.
• Give 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.
• Confirm pregnancy termination 14 days after initial dose.

Route	Onset	Peak	Duration
P.O.	Rapid	90 min	11 days

Adverse reactions

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

EENT: sinusitis

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

GU: vaginitis, leukorrhea, uterine cramping, pelvic pain, uterine hemorrhage

Hematologic: anemia

Musculoskeletal: leg pain, back pain

Skin: fever

Other: viral infections

Interactions

Drug-drug. Carbamazepine, dexamethasone, phenobarbital, phenytoin, rifampin: decreased mifepristone blood level and effects

Drugs metabolized by CYP450-3A4: decreased mifepristone metabolism and increased effects

Erythromycin, itraconazole, ketoconazole: inhibited mifepristone metabolism and increased blood level

Drug-diagnostic tests. Hematocrit, hemoglobin: decreased values

Red blood cells: decreased count

Drug-food. Grapefruit juice: 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.

Patient teaching

• After administration, tell patient she'll need to return in 48 hours for a prostaglandin drug or to verify pregnancy termination.
• Tell patient she'll 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'll need follow-up appointment 2 weeks later to verify pregnancy termination.
• Inform patient that she's at risk for pregnancy right after abortion is complete. Encourage appropriate contraceptive decision.
• As appropriate, review all other significant and life-threatening adverse reactions and interactions, especially those related to the drugs, tests, and foods mentioned above.