AB Kit

Approved Indications (Early Medical Abortion)

• Termination of intrauterine pregnancy up to 70 days gestation (≤10 weeks).
• Used in combination: mifepristone (600 mg PO) followed 24–48 h later by misoprostol (400 µg buccally or vaginally).

Important Off‑Label or Clinically Accepted Uses

• Management of missed or incomplete miscarriage (≤70 days), using same dosing schedule to induce uterine expulsion.
• Mifepristone pretreatment (200–600 mg) followed by misoprostol for later first-trimester or second-trimester pregnancy loss.
• Cervical ripening before surgical procedures (e.g., dilation & evacuation), with lower-dose protocols.

Adults (≥18 years) – Medical abortion

• Day 1: Mifepristone 600 mg orally (single dose).
• Day 2–3 (24–48 h later): Misoprostol 400 µg buccally or vaginally, may repeat once after 3–6 h if needed.

Menstrual-/Missed‑Miscarriage

• Same regimen used for abortion applies; misoprostol may be repeated up to a total of 4 doses (maximum 1600 µg).

Pediatrics (Post‑menarche & ≤17 years)

• Use same adult dose and timing under specialist guidance; efficacy and safety parallels adult data.

Elderly

• Not applicable (no indication).

Renal/Hepatic Impairment

• No dose adjustments recommended; limited data but metabolites are not heavily dependent on renal/hepatic clearance at these doses.

Administration Notes

• Avoid oral misoprostol for abortion—local buccal or vaginal routes preferred to maximize uterine effect and minimize GI side effects.

Mifepristone is a competitive antagonist at progesterone receptors, interrupting progesterone-mediated support of the endometrium and leading to decidual breakdown. It also increases uterine contractility and cervical softening by sensitizing the myometrium to prostaglandins. Misoprostol, a prostaglandin E₁ analog, induces uterine contractions and cervix dilation, facilitating expulsion of uterine contents. This sequential action ensures complete termination or evacuation.

Absorption:

• Mifepristone is rapidly absorbed orally (peak ~1–2 h).
• Misoprostol is absorbed via buccal/vaginal routes; buccal peaks at ~1 h.

Distribution:

• Mifepristone highly protein‑bound (>98%), large volume of distribution.
• Misoprostol acid (active metabolite) moderately bound.

Metabolism:

• Mifepristone metabolized by CYP3A4 to active and inactive metabolites; half-life ~18–25 h.
• Misoprostol is swiftly deesterified to its active form; half-life ~20–40 minutes.

Excretion:

• Mifepristone and metabolites via biliary and renal routes.
• Misoprostol metabolites eliminated in urine.

Pregnancy:

• Contraindicated when used for abortion outside approved gestational age. Use category X as per FDA for pregnancy interruption (intended).

Lactation:

• Misoprostol and mifepristone may pass into breast milk in small amounts.
• Breastfeeding may continue after abortion, but express and discard milk for 36–48 h post-mifepristone to allow elimination.
• Caution advised due to theoretical risk of uterine side effects in the infant (rare).

• Primary class: Antiprogestin (mifepristone) + Prostaglandin analog (misoprostol).
• Subclass: Abortifacient/prostaglandin E₁ analog.

• Known allergy to mifepristone, misoprostol, or prostaglandin analogs.
• Ectopic pregnancy (ruptured or suspected).
• Chronic adrenal failure (due to mifepristone’s glucocorticoid antagonism).
• Simultaneous long‑term corticosteroid therapy.
• Hemorrhagic disorders or on anticoagulants with high bleeding risk.
• Severe anemia (Hb < 9 g/dL).
• Inability to access emergency medical care.

• High-risk groups: Anemic patients, adrenal insufficiency.
• Severe risk: Heavy bleeding (occurring in ~5%), including hemorrhage.
• Monitoring: Confirm completion via ultrasound/hCG tests. Watch for infection, excessive bleeding, or sepsis.
• Early warning signs: Fever >38 °C, severe abdominal pain with dizziness, hypovolemia—requires urgent care.

Common (Systemic):

• GI upset: nausea, vomiting, diarrhea, abdominal cramps (around misoprostol dosing).
• Headache, dizziness, fatigue.

Gynecologic/Reproductive:

• Heavy uterine bleeding 24–48 h post-misoprostol; cramps moderate to severe during expulsion.
• Transient spotting up to 14 days.

Rare/Serious:

• Endometrial infection, sepsis (especially with fever >37.8 °C ≥ 24 h).
• Uterine rupture in late pregnancy use (very rare).
• Hypovolemic shock due to hemorrhage.

• CYP3A4 inducers (e.g., rifampin, carbamazepine, phenytoin): may reduce mifepristone levels → decreased efficacy.
• CYP3A4 inhibitors (e.g., ketoconazole, itraconazole): may increase mifepristone concentrations, raising risk of cortisol receptor antagonism/adrenal insufficiency.
• Anticoagulants/antiplatelets (e.g., warfarin): increased bleeding risk due to induced uterine bleeding.
• Alcohol: may exacerbate GI effects and dehydration—advise avoidance.

• WHO (2023): Expanded indication to ≤70 days; endorses home-based use up to 63 days.
• NICE (2024, UK): Confirms home use safe and effective for ≤10 weeks, with remote follow‑up via telehealth.
• FDA (2024): Approved buccal misoprostol route; clarified safety data.
• ACOG (2022): Recommends 200 mg mifepristone alternative (vs. 600 mg) with similar outcomes; adoption underway in some regions.

• Mifepristone tablets: Store at 20–25 °C (68–77 °F); brief excursions 15–30 °C allowed. Keep in original blister until use; protect from moisture and light.
• Misoprostol tablets: Store at ≤25 °C; tightly sealed in original container with desiccant to prevent humidity exposure; avoid freezing.
• Reconstitution not applicable. If any off-label compounding: refrigerate 2–8 °C and use within 14 days; discard if not used.