Mifegyne (Mifepristone)

Mifegyne is a progesterone receptor antagonist employed in early pregnancy termination.

• Medical termination of intrauterine pregnancy up to 10 weeks gestation: induces decidual breakdown and facilitates expulsion of the gestational sac.
• Pre‑treatment before misoprostol in medical abortion protocols: enhances the efficacy of the prostaglandin analogue used to complete the abortion.
• Early intrauterine pregnancy up to 7 weeks: provides a medically supervised option for termination within the approved gestational window.

• Mifepristone binds competitively to progesterone receptors in the endometrium, blocking the hormone's action. This antagonism leads to decidual degeneration, detachment of the gestational sac, and increased uterine sensitivity to prostaglandins, thereby facilitating medical termination when followed by a prostaglandin analogue such as misoprostol.

Mifegyne may cause a range of adverse reactions, most of which are mild and transient.

Common Side Effects

• Nausea: mild to moderate upset stomach.
• Vaginal bleeding: spotting or heavier flow.
• Abdominal cramping: uterine contractions.
• Diarrhea: loose stools.
• Fatigue: general tiredness.
• Headache: mild pain in the head.

Serious or Rare Side Effects

• Severe infection: signs of fever or sepsis.
• Heavy bleeding: excessive blood loss requiring medical attention.
• Allergic reaction: rash, swelling, or difficulty breathing.
• Liver dysfunction: jaundice or abnormal liver tests.
• Uterine rupture: rare but life‑threatening emergency.
• Persistent gestational sac: incomplete abortion requiring surgical intervention.

Mifegyne should be used only under qualified medical supervision with attention to specific safety considerations.

• Confirm gestational age: ensure pregnancy is ≤10 weeks.
• Medical supervision: procedure must be overseen by a trained health professional.
• Contraindications: avoid in chronic adrenal failure, long‑term corticosteroid therapy, anticoagulant use, or intrauterine device presence.
• Allergy assessment: do not use if hypersensitivity to mifepristone or any excipients is known.
• Drug interaction review: evaluate concomitant medications that may affect efficacy or safety.
• Store at below 25°C: keep in the original packaging, protect from moisture and direct sunlight.

Mifegyne can interact with several medicines, requiring careful management.

Major Interactions (Avoid)

• CYP3A4 inducers (e.g., rifampin, carbamazepine): may markedly reduce mifepristone effectiveness.
• Anticoagulants (e.g., warfarin, heparin): increase risk of significant bleeding.

Moderate Interactions (Monitor Closely)

• Misoprostol: required for complete abortion; timing and dosing must be coordinated.
• Hormonal contraceptives: may diminish contraceptive efficacy after abortion.
• NSAIDs: can exacerbate gastrointestinal discomfort.
• Antifungal azoles (e.g., ketoconazole): may increase mifepristone plasma levels.
• Antidepressants (e.g., sertraline): monitor for additive nausea or dizziness.