Methergin (Methylergometrine)

Methylergometrine acts as a uterotonic agent used in obstetric practice to manage bleeding and support labor.

• Postpartum hemorrhage: helps prevent excessive bleeding after delivery.
• Uterine atony: restores uterine tone to reduce bleeding.
• Labor induction: facilitates cervical dilation and uterine contractions during induction of labor.

• Methylergometrine exerts its uterotonic effect by partially agonizing serotonin 5‑HT2 receptors and antagonizing dopamine D2 receptors in uterine smooth muscle. This dual action increases intracellular calcium, leading to sustained uterine contraction and reduced uterine blood flow, thereby controlling hemorrhage and supporting labor processes.

Methylergometrine may cause a range of adverse reactions, from mild to severe.

Common Side Effects

• Nausea: mild to moderate stomach upset.
• Vomiting: occasional emesis after dosing.
• Headache: transient cranial discomfort.
• Hypertension: modest rise in blood pressure.
• Abdominal pain: cramping in the lower abdomen.
• Flushing: temporary reddening of the skin.

Serious or Rare Side Effects

• Severe hypertension: marked elevation of blood pressure requiring medical attention.
• Coronary artery spasm: chest pain or ischemic symptoms.
• Myocardial infarction: rare heart attack events.
• Seizures: occasional convulsive episodes.
• Pulmonary edema: fluid accumulation in the lungs.
• Anaphylaxis: life‑threatening allergic reaction.

Methylergometrine requires careful assessment before use due to its potent vasoconstrictive properties.

• Pregnancy: contraindicated (Category X); avoid in pregnant women not in labor.
• Cardiovascular disease: avoid in patients with coronary artery disease or uncontrolled hypertension.
• Hypertension: monitor blood pressure closely during therapy.
• Liver impairment: use with caution; dose adjustment may be needed.
• Drug interactions: review concomitant medications for potential additive effects.
• Store at ambient temperature below 25°C: keep in the original pack, protect from moisture and light.

Methylergometrine can interact with several drug classes, influencing safety and efficacy.

Major Interactions (Avoid)

• MAO inhibitors: risk of severe hypertensive crisis.
• Other ergot derivatives: additive vasospasm and ischemia.
• Potent CYP3A4 inhibitors: increased plasma concentrations, heightening toxicity.

Moderate Interactions (Monitor Closely)

• Antihypertensives: may diminish blood‑pressure‑lowering effect.
• SSRIs: potential for serotonin syndrome.
• Calcium channel blockers: enhanced vasoconstriction risk.