Mifepristone-Misoprostol

• Medication Abortion
• Early Pregnancy Termination

Mifepristone and misoprostol is a two-drug regimen approved for medical termination of early pregnancy. This combination is also known as medication abortion or the "abortion pill." When used together, these medications provide a safe and effective non-surgical option for pregnancy termination.

Mechanism of Action

Mifepristone:

• Synthetic anti-progestational compound
• Binds to progesterone receptors with high affinity, blocking progesterone action
• Causes decidual necrosis, cervical softening, and increases uterine sensitivity to prostaglandins
• Increases prostaglandin synthesis

Misoprostol:

• Synthetic prostaglandin E1 analog
• Causes uterine contractions and cervical ripening
• Completes the expulsion of uterine contents

Together, these medications achieve pregnancy termination rates exceeding 95% when used through 70 days of gestation.

Available Formulations

Mifepristone (Mifeprex):

• 200 mg tablet (single dose)

Misoprostol:

• 200 mcg tablets (4 tablets = 800 mcg used buccally or vaginally)

The regimen is available only through the Mifeprex REMS (Risk Evaluation and Mitigation Strategy) program from certified prescribers and pharmacies.

Medical Uses

FDA-Approved Indication:

• Medical termination of intrauterine pregnancy through 70 days gestation

The regimen is not approved for ectopic pregnancy and will not treat this condition.

Dosing Guidelines

Standard FDA-Approved Regimen:

1. Day 1: Mifepristone 200 mg orally
2. 24-48 hours later: Misoprostol 800 mcg buccally (held in cheeks for 30 minutes, then swallow remaining)

Alternative administration (off-label but evidence-based):

• Misoprostol can be administered vaginally

Follow-up:

• Assessment within 7-14 days to confirm complete termination
• Assessment can be done via telehealth with home urine pregnancy testing or clinic visit

Important Safety Information

REMS Requirements:

• Must be prescribed by or under supervision of certified prescriber
• Patient must sign Patient Agreement Form
• Must be dispensed in healthcare setting, clinic, or certified pharmacy

Contraindications:

• Confirmed or suspected ectopic pregnancy
• IUD in place (must be removed first)
• Chronic adrenal failure
• Concurrent long-term corticosteroid therapy
• Hemorrhagic disorders or concurrent anticoagulant therapy
• Known allergy to mifepristone, misoprostol, or other prostaglandins
• Inherited porphyrias

Warnings and Precautions:

• Serious infections and sepsis have occurred (rare)
• Heavy bleeding requiring transfusion (rare)
• Incomplete abortion may require surgical intervention
• Rh immunoglobulin should be given to Rh-negative patients

Drug Interactions

• CYP3A4 inducers (rifampin, phenytoin, carbamazepine): May reduce mifepristone levels
• CYP3A4 inhibitors (ketoconazole, grapefruit juice): May increase mifepristone levels
• Corticosteroids: Mifepristone may reduce corticosteroid effects
• Anticoagulants: Increased bleeding risk

Expected Course

• Bleeding typically begins within 24-48 hours after misoprostol
• Heavy bleeding and cramping are expected and may last several hours
• Lighter bleeding may continue for 9-16 days
• Return to fertility can occur within weeks; contraception should be discussed

Emergency Situations

Patients should seek immediate care if experiencing:

• Heavy bleeding (soaking >2 thick pads/hour for 2+ hours)
• Fever >100.4°F persisting more than 24 hours
• Severe abdominal pain not relieved by ibuprofen
• Weakness, nausea, vomiting, or diarrhea more than 24 hours after misoprostol