Misoprostol is a synthetic prostaglandin E1 (PGE1) analogue. It is a potent gastric antisecretory and mucosal protective agent, and a powerful uterotonic. In the Indian context, it is a critical drug for obstetric and gynecological care, widely used for medical termination of pregnancy (MTP), cervical ripening, and postpartum hemorrhage (PPH) prevention, as well as for NSAID-induced gastric ulcer prophylaxis. Its use is strictly regulated under Schedule H and the MTP Act.
Adult: **Gastric Ulcer Prophylaxis (with NSAIDs):** 200 mcg QID with food (last dose at bedtime). Can reduce to 200 mcg BD-TID or 400 mcg BD. **MTP (with Mifepristone):** Mifepristone 200 mg orally single dose, followed 36-48 hours later by Misoprostol 800 mcg vaginally/buccally/sublingually. **PPH Prevention:** 600 mcg orally immediately after delivery. **Cervical Ripening:** 400 mcg vaginally 3-4 hours prior to procedure.
Note: **For Gastric Protection:** Take with meals and at bedtime to minimize diarrhea. **For Obstetric Use:** Vaginal administration: Insert tablet(s) high into posterior fornix. Buccal: Place between cheek and gum for 30 minutes, swallow remnants. Sublingual: Place under tongue for 30 minutes, swallow remnants. Do not crush or chew tablets intended for vaginal/buccal use. Must be administered under direct medical supervision for MTP/obstetric indications.
Misoprostol replaces protective prostaglandins that are depleted by NSAIDs and exerts dual action: 1) Gastric: Inhibits basal, nocturnal, and stimulated gastric acid secretion via direct action on parietal cells. It increases bicarbonate and mucus secretion, enhancing mucosal blood flow and cytoprotection. 2) Uterine: Binds to prostaglandin receptors (EP2/EP3) on uterine smooth muscle, causing strong, sustained contractions. It also softens and dilates the cervix by promoting collagen breakdown.
Pregnancy: **CATEGORY X.** Absolutely contraindicated in pregnant women for the prevention of NSAID-induced ulcers due to its abortifacient property. Its use is ONLY intended for medical termination of pregnancy or other obstetric indications under strict medical supervision. Can cause fetal demise, birth defects (e.g., cranial nerve palsies, facial malformations, limb defects), and miscarriage.
Driving: May cause dizziness or drowsiness in some patients. Patients should be cautioned about operating machinery or driving until they know how the drug affects them, especially during initial therapy.
| Antacids (Magnesium-containing) | Increased incidence and severity of diarrhea. | Moderate |
| Oxytocin, other uterotonics | Potentiates uterine contractions, risk of hyperstimulation/rupture. | Major |
| NSAIDs (e.g., Aspirin, Ibuprofen) | Therapeutic synergy for gastric protection, but NSAIDs may antagonize the cytoprotective effect of misoprostol to some degree. | Moderate |
| Corticosteroids | May increase risk of GI ulceration; misoprostol mitigates this. | Moderate |