Methergine (Methylergonovine) Dosing for Uterine Atony
For uterine atony refractory to oxytocin, methylergonovine 0.2 mg intramuscular is the standard dose, not 0.125 mg. 1, 2
Standard Dosing Protocol
The 0.125 mg tablet formulation you mentioned is not the recommended dose for acute uterine atony management. The evidence-based dosing is:
- Methylergonovine 0.2 mg intramuscular is the established second-line uterotonic dose for oxytocin-refractory uterine atony 1, 2
- This 0.2 mg dose demonstrates equivalent efficacy to carboprost tromethamine (another second-line agent), with mean uterine tone scores of 7.3±1.7 at 10 minutes post-administration 2
- The 0.2 mg dose can be repeated if needed, though specific repeat-dosing intervals are not standardized in the literature 1
Clinical Context
Methylergonovine works as a second-line agent when oxytocin fails to restore adequate uterine tone:
- Oxytocin remains the first-line agent for both prevention and treatment of uterine atony 3, 1
- For cesarean delivery, oxytocin bolus doses of 1 IU (elective) to 3 IU (intrapartum) are typically sufficient 3
- When uterine atony persists despite oxytocin, second-line agents like methylergonovine should be administered early rather than delayed 3
- Approximately 30% of patients receiving methylergonovine 0.2 mg may require additional second-line uterotonics 2
Route of Administration
- Intramuscular injection is the standard route for acute uterine atony management 1, 2, 4
- Oral tablet formulations exist but are not appropriate for acute hemorrhage scenarios requiring immediate uterotonic effect 1
Critical Contraindications
Before administering methylergonovine, verify the patient does not have:
- Hypertension or preeclampsia (methylergonovine causes vasoconstriction and can precipitate hypertensive crisis) 1
- Coronary artery disease or peripheral vascular disease 1
- Sepsis 1
Alternative Second-Line Agents
If methylergonovine is contraindicated:
- Carboprost tromethamine 250 mcg intramuscular demonstrates equivalent efficacy (mean 10-minute uterine tone score 7.6±2.1) 2
- Carboprost is contraindicated in asthma but may be used in hypertensive patients 1
- Misoprostol 800-1000 mcg (sublingual or rectal) is less effective than methylergonovine or carboprost but useful in resource-limited settings 3, 1, 4
Common Pitfall to Avoid
Do not use the 0.125 mg dose for acute uterine atony—this underdoses the patient and delays effective hemorrhage control. The 0.2 mg intramuscular dose is the evidence-based standard that has been validated in randomized trials. 1, 2