What is the dosage and administration of buccal misoprostol (prostaglandin E1 analog) for labor induction, abortion, or prevention of postpartum hemorrhage?

Buccal Misoprostol Dosage and Administration Guidelines

For medical abortion, labor induction, and postpartum hemorrhage prevention, buccal misoprostol should be administered at specific doses based on indication: 800 mcg every 3 hours for three doses for early abortion, 200-400 mcg for cervical ripening in selected cases, and 600 mcg orally for postpartum hemorrhage prevention.

Medical Abortion

Dosage and Administration

• Early abortion (first trimester): 800 mcg buccal misoprostol every 3 hours for three doses 1
  • Place tablets between cheek and gums, allow to dissolve for 30 minutes
  • Sublingual administration (under the tongue) may be more effective in preventing continuing pregnancy (1.1% vs 5.5% failure rate) 1
  • Follow-up within 7-14 days to confirm complete abortion

Efficacy and Side Effects

• Complete abortion rates: 84.6% (buccal) vs 87.3% (sublingual) after initial treatment 1
• Additional misoprostol at follow-up increases success to >92% for both routes 1
• Side effects include:
  • Abdominal pain (94.6%)
  • Vaginal bleeding (98.6%)
  • Nausea, vomiting, diarrhea
  • Fever and chills (more common with sublingual administration) 2, 1

Labor Induction

Dosage and Administration

• Misoprostol is not recommended for labor induction in women with previous cesarean delivery or major uterine surgery 3, 4
• For cervical ripening in selected cases:
  • 200 mcg vaginal misoprostol (10 and 4 hours prior) for patients with previously failed IUD insertion 3
  • 400 mcg vaginal misoprostol (4 hours prior) may decrease pain during IUD placement in nulliparous patients 3

Precautions and Contraindications

• Contraindicated in third trimester for women with previous cesarean section due to risk of uterine rupture 4
• Not recommended when uterotonic drugs are contraindicated or hyperstimulation is inappropriate 4
• Should be administered in hospital setting with continuous monitoring 2, 5
• Mechanical methods for cervical ripening are preferable to pharmacological agents in patients with cyanosis 3

Postpartum Hemorrhage Prevention

Dosage and Administration

• Prevention: 600 mcg oral misoprostol 6
• Treatment: 800 mcg sublingual misoprostol as first-line treatment 6

Administration Considerations

• Slow IV infusion of oxytocin (<2 U/min) is preferred after placental delivery 3
• Misoprostol should not be given less than 4 hours prior to initiating oxytocin treatment 4
• Monitor for side effects including transient high fever (>40°C), tachycardia, disorientation 4

Important Warnings and Precautions

• High doses (200 mcg vaginal) for term labor induction have been associated with precipitate delivery and postpartum hemorrhage 7
• Misoprostol can cause uterine tachysystole, tetany, and rupture 4
• Fetal monitoring is essential when used for obstetric indications 4
• Misoprostol is teratogenic when used unsuccessfully for abortion; congenital anomalies have been reported 4
• Use with caution in patients with cardiovascular disease as it can lower systemic vascular resistance 2

Special Considerations

• Misoprostol is rapidly metabolized to misoprostol acid, which is excreted in breast milk 4
• Safety in pediatric patients has not been established 4
• For all obstetric uses, hospital administration with close monitoring is strongly recommended 5

Remember that misoprostol is often used off-label for obstetric and gynecologic indications, and the benefits must be carefully weighed against the risks in each clinical scenario.