Misoprostol is a synthetic prostaglandin E1 (PGE1) analogue with potent antisecretory, mucosal protective, and uterotonic properties. In the Indian context, it is a critical drug for obstetric and gynecological care, widely used for medical termination of pregnancy (MTP) and postpartum hemorrhage (PPH) prevention, especially in resource-limited settings. It is also used for gastric ulcer prophylaxis in patients on NSAIDs, though this use is less common.
Adult: **MTP (with Mifepristone):** Mifepristone 200mg orally, followed 36-48 hours later by Misoprostol 800mcg buccally/vaginally or 400mcg sublingually. For pregnancies 9-12 weeks, may require additional doses. **PPH Prevention:** 600mcg orally immediately after delivery. **PPH Treatment:** 800-1000mcg sublingually/rectally. **Gastric Ulcer Prophylaxis:** 200mcg QID with food, last dose at bedtime.
Note: **For MTP:** Tablets can be placed in the buccal pouch (between cheek and gum) for 30 minutes, swallowed remnants with water. Vaginal administration is also effective. **For GI use:** Take with meals and at bedtime to reduce diarrhea. Do not crush or chew tablets intended for buccal/vaginal use. For oral use, swallow whole with water.
Misoprostol acts by binding to specific prostaglandin receptors (EP2/EP3 subtypes) on target cells. Its effects are organ-specific: 1) Gastric Mucosa: It inhibits basal, nocturnal, and stimulated gastric acid secretion. It increases bicarbonate and mucus secretion, enhancing mucosal blood flow and cytoprotection. 2) Uterus: It binds to myometrial prostaglandin receptors, causing strong, rhythmic contractions of the uterine smooth muscle, leading to cervical softening, dilation, and expulsion of uterine contents.
Pregnancy: **CATEGORY X for all indications except MTP/obstetric use.** It is a known abortifacient and can cause fetal malformations (e.g., cranial nerve defects, limb abnormalities) if used during pregnancy for GI protection. For MTP, its use is intentional and supervised.
Driving: May cause dizziness or drowsiness in some patients. Caution advised until individual response is known.
| Magnesium-containing Antacids | Increased incidence of diarrhea | Moderate |
| Oxytocin, other Oxytocics | Synergistic uterotonic effect, risk of uterine hyperstimulation/rupture | Major |
| NSAIDs (e.g., Aspirin, Ibuprofen) | May attenuate the gastric cytoprotective effect of misoprostol | Moderate |
| Anticoagulants (Warfarin, DOACs) | Potential increased risk of bleeding during obstetric procedures | Moderate |