Dosing and uses of Methergine (methylergonovine)
Adult dosage forms and strengths
injectable solution
- 0.2mg/mL
tablet
- 0.2mg
Postpartum Hemorrhage
0.2 mg IM/IV q2-4hr PRN; not to exceed 5 doses, THEN 0.2-0.4 mg PO q6-8hr PRN for 2-7 days
Administer IV only in emergency because of potential for Hypertension & CVA
Administer over >1 minute and monitor Bp
Refractory Cluster Headache (Off-label)
0.2 mg PO q6-8hr, not to exceed 6 months
Pediatric dosage forms and strengths
Not applicable
Methergine (methylergonovine) adverse (side) effects
Frequency not defined
Nausea/vomiting
Dizziness
Headache
Tinnitus
Diaphoresis
Palpitation
Transient chest pain
Dyspnea
Thrombophlebitis
Hematuria
Water intoxication
Hallucinations
Leg cramps
Nasal congestion
Diarrhea
Foul taste
Allergic phenomena including shock
Hypertension
Postmarketing reports
Nervous system: Cerebrovascular accident, paraesthesia
Cardiovascular: Ventricular fibrillation, ventricular tachycardia, angina pectoris, atrioventricular block
Warnings
Contraindications
(All not necessarily unanimous): Hypertension, heart disease, toxemia, pregnancy, hypersensitivity, mitral valve stenosis, prolonged use
Cases of threatened spontaneous abortion
Avoid during breastfeeding
Cautions
Second or third stage of labor prior to placenta delivery: complications such as captivation of placenta may occur; avoid accidental injection to newborn babies
Increased risk of myocardial ischemia and infarction with coronary artery disease or risk factors for coronary artery disease
Sepsis, hepatic impairment, renal impairment, peripheral vascular disease
Prolonged use may cause pleuropulmonary, cardiac or retroperitoneal fibrosis
Pregnancy and lactation
Pregnancy category: C
Lactation: Excreted in milk; adverse effect on nursing infant; may inhibit lactation; not recommended
Wait at least 12 hours after last dose to breastfeed
Pregnancy categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk.
C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done.
D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk.
X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist.
NA: Information not available.
Pharmacology of Methergine (methylergonovine)
Mechanism of action
Produces vasoconstriction to increase strength, duration, & frequency of uterine contraction which in turn impedes uterine blood flow
Pharmacokinetics
Bioavailability: 60% (PO); 78% (IM)
Peak Plasma Time: 30 min
Peak Plasma Concentration: 3 ng/mL
Onset: uterine contractions are usually initiated within 5-15 min following oral administration, within 2-5 min after IM injection, & immediately following IV injection
Duration: 3 hr (PO); 3hr (IM); 45 min (IV)
Vd: 39-73L
Metabolism: Liver
Excretion: Urine and feces
Half-Life
- Initial phase: 1-5 min
- Terminal phase: 0.5-2 hr
Administration
IV Administration
Give IV only in emergency because of potential for HTN & CVA
Give over >1 min & monitor BP & uterine contractions
