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Misoprostol

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Misoprostol, Cytotec, PGE1 Gel

  • See Also
  1. Misoprostol Poisoning
  2. Peptic Ulcer Disease
  3. Cervical Ripening
  4. Early Pregnancy Loss
  5. Mifepristone and Misoprostol Protocol for Early Pregnancy Loss
  • Indications
  1. Peptic Ulcer Disease Prevention
    1. See NSAID Gastrointestinal Adverse Effects
    2. Prevents ulcers in those on NSAIDs chronically
  2. Cervical Ripening agent in Pregnancy Labor Induction
  3. Termination of Pregnancy (<77 days)
  4. Early Pregnancy Loss (<84 days)
    1. See Mifepristone and Misoprostol Protocol for Early Pregnancy Loss
  • Contraindications
  1. Factors that increase risk for Uterine Rupture
    1. Prior Cesarean Section
    2. Multigravida with >=5 prior pregnancies (relative contraindication)
  • Mechanism
  1. See Prostaglandin
  2. Misoprostol is a synthetic Prostaglandin E1 (PGE1) Analog
    1. Misoprostol is a pro-drug, that when taken orally is de-esterified to its active acid
    2. Misoprostol activity as a PGE1 Analog is local at the Uterus and gastric mucosa with non-toxic doses
      1. Contrast with systemic PGE1 effects absent with Misoprostol (e.g. vasodilation, bronchodilation)
  3. Prostaglandin E1 (PGE1) Local Effects
    1. Cervical Ripening and uterine contractions
    2. Gastric Mucosa Protection by Prostaglandin replacement
      1. Inhibits gastric acid and pepsin secretion (dose dependent)
      2. Bolsters mucosal resistance to injury
  • Medications
  1. Misoprostol (Cytotec) oral tablets: 100 mcg, 200 mcg
    1. Oral tablets may be used intravaginally
  1. See NSAID Gastrointestinal Adverse Effects
  2. Option 1: 100 to 200 mcg four times daily with food
  3. Option 2: 200 mcg orally twice daily with food
    1. Better tolerated than four times per day dosing
  • Dosing
  • Obstetrics and Gynecology
  1. Cervical Ripening
    1. See Cervical Ripening for complete protocol
    2. Misoprostol 50 mcg per vagina every 6 hours (or 25 mcg every 3 hours)
    3. Monitor for uterine hyperstimulation and Fetal Heart Rate
    4. Avoid after prior Cesarean Section, Multigravida (>=5 prior pregnancies)
      1. Risk of Uterine Rupture
  2. Early Pregnancy Loss (<84 days) or Termination of Pregnancy (<77 days)
    1. See Early Pregnancy Loss (includes precautions and monitoring protocol)
    2. See Mifepristone and Misoprostol Protocol for Early Pregnancy Loss
    3. Misoprostol Dosing Protocol
      1. Vaginal (or rectal)
        1. Place 800 mcg (4 tablets) intravaginally at 24-48 hours after Mifepristone
        2. Lie supine for 30 minutes after dose
      2. Buccal Dosing may be used in place of vaginal dosing
        1. Place two of the 200 mcg Misoprostol tablets on each side of the mouth (total 800 mcg)
        2. Allow tablets to dissolve over 30 minutes
      3. Efficacy improves if followed by second dose Misoprostol 800 mcg 4 hours after first
    4. Strong uterine cramping and heavier Vaginal Bleeding follows Misoprostol dose
      1. Onset within several hours
      2. Persists for 3-5 hours
      3. Lighter Vaginal Bleeding may persist for 9-16 days
    5. Adjunctive medications
      1. NSAIDs
      2. Heating pad
  • Pharmacokinetics
  1. Rapid oral absorption
  2. Serum level peaks within 30 min of oral dose
  3. Elimination half life (including metabolites): <2 hours
  • Safety
  1. Pregnancy Category X (aside from peripartum Cervical Ripening, pregnancy loss)
  2. Avoid in Lactation
  • Adverse Effects
  1. See Misoprostol Poisoning
  2. When used orally (poorly tolerated)
    1. Diarrhea
    2. Nausea
    3. Vomiting
    4. Abdominal cramping
    5. Flatulence
  3. Gynecologic symptoms (800 mcg dosing)
    1. Strong uterine cramping
    2. Vaginal Bleeding heavier than typical Menses
  1. Dosing four times daily: 4% Peptic Ulcer Disease recurrence
  2. Dosing twice daily: 8% Peptic Ulcer Disease recurrence
  3. Placebo: 16% Peptic Ulcer Disease recurrence
  4. Reference
    1. Raskin (1995) Ann Intern Med 123:344-50 [PubMed]
  • Resources
  1. Misoprostol (DailyMed)
    1. https://dailymed.nlm.nih.gov/dailymed/drugInfo.cfm?setid=f15b41bd-ed36-4908-aba5-f0a019b7a26e
  • References
  1. MacNaughton (2021) Am Fam Physician 103(8) 473-80 [PubMed]