Head-to-head clinical analysis & difference comparison: details on mechanism of action, dosing, half-life, interactions, and maternal-fetal safety.
Ergometrine / Methylergonovine vs AMINOPHYLLINE IN SODIUM CHLORIDE 0.45%
Clinician-reviewed, head-to-head comparison of mechanism, dosing, pharmacokinetics, and safety profiles.
Last clinically reviewed: July 2026 · OpiCalc Medical Review Team
Ergometrine and methylergonovine are ergot alkaloids that act as partial agonists at alpha-adrenergic, dopaminergic, and serotonergic (5-HT2) receptors. Their primary uterotonic effect is mediated by stimulation of 5-HT2 receptors in uterine smooth muscle, leading to sustained contractions and vasoconstriction.
Aminophylline is a complex of theophylline and ethylenediamine, acting as a phosphodiesterase inhibitor, increasing intracellular c AMP levels; nonselective adenosine receptor antagonist; enhances cardiac inotropy, bronchodilation, and CNS stimulation.
Prevention and treatment of postpartum hemorrhage (FDA approved),Uterine atony (FDA approved),Ovarian hyperstimulation syndrome (off-label),Variceal bleeding (off-label),Migraine headache (off-label)
Treatment of acute bronchospasm in asthma and COPD,Reversal of dipyridamole-induced adverse effects during stress testing,Apnea of prematurity (off-label),Status asthmaticus (off-label)
0.2 mg intramuscularly or intravenously, repeated every 2-4 hours as needed, up to 5 doses total. Maximum single dose: 0.5 mg. Maximum total dose: 1 mg.
Loading dose: 5-6 mg/kg IV over 20-30 minutes, then continuous infusion: 0.5-0.7 mg/kg/hour IV.
30-120 min (biphasic: initial 10 min, terminal 30-120 min); clinical context: short half-life allows repeated dosing for postpartum hemorrhage but requires monitoring for accumulation
Terminal elimination half-life is 6-12 hours in adults, 1-5 hours in children (due to faster clearance), 20-30 hours in premature neonates, and 10-15 hours in patients with hepatic cirrhosis or heart failure. Clinical context: dosing interval adjustment required based on half-life; prolonged half-life in hepatic impairment or cardiac decompensation increases risk of toxicity.
Primarily hepatic via CYP3A4; also undergoes first-pass metabolism. Metabolites are excreted in urine and bile.
Hepatic via cytochrome P450 enzymes (CYP1A2, CYP3A4, CYP2E1); saturable kinetics; extensive first-pass metabolism.
Renal (20% unchanged), biliary/fecal (35% as metabolites and parent compound)
Renal excretion of unchanged theophylline (10-20%) and metabolites (80-90%). In neonates, renal excretion of unchanged drug is higher (up to 50%). Biliary/fecal excretion is negligible.
85-90% (primarily to albumin and α1-acid glycoprotein)
Approximately 40% bound to plasma proteins, mainly albumin. In neonates, preterm infants, and patients with hepatic cirrhosis, protein binding is reduced (free fraction increases). Binding is also saturable at high theophylline concentrations.
0.4-0.6 L/kg; clinical meaning: moderate tissue distribution, consistent with limited extravascular binding
Volume of distribution is approximately 0.45 L/kg (range 0.3-0.7 L/kg) in adults. In neonates, Vd is larger (~0.6-0.8 L/kg). Clinical meaning: Vd indicates extensive distribution into body water; loading doses are calculated using Vd (e.g., 1 mg/kg raises serum concentration by ~2 mcg/m L).
Oral: 20-40% (due to extensive first-pass metabolism); IM: ~80%
Oral immediate-release: 100% (well absorbed). Rectal: 80-100% (absorption may be erratic). IV: 100%. No significant first-pass metabolism.
No specific guidelines; use with caution in severe renal impairment (GFR <30 m L/min) due to risk of accumulation and hypertensive effects.
No specific dose adjustment required for GFR >10 m L/min. For GFR <10 m L/min, reduce infusion rate by 50%.
Child-Pugh Class A: no adjustment. Child-Pugh Class B: reduce dose by 50% or extend interval. Child-Pugh Class C: avoid use.
Child-Pugh Class A: reduce dose by 25%; Class B: reduce dose by 50%; Class C: reduce dose by 75%.
0.1-0.2 mg intramuscularly or intravenously every 2-4 hours as needed; maximum single dose 0.2 mg. For postpartum hemorrhage, 0.2 mg IM/IV repeated every 2-4 hours, max 5 doses.
Loading dose: 5-6 mg/kg IV over 20-30 minutes; continuous infusion: 0.5-0.7 mg/kg/hour (age-dependent, with lower doses for younger children).
Use lowest effective dose due to increased sensitivity and higher risk of hypertension and coronary vasospasm; consider 0.1 mg initially and titrate cautiously.
Elderly patients may have reduced clearance; consider starting at the lower end of dosing range (e.g., 0.3-0.5 mg/kg/hour) and titrate based on serum levels.
Concurrent use with potent CYP3A4 inhibitors (e.g., macrolide antibiotics, protease inhibitors, azole antifungals) may result in acute ergot toxicity (vasospasm, cerebral and peripheral ischemia). Contraindicated in pregnancy for induction of labor due to risk of uterine rupture and fetal harm.
Theophylline toxicity is dose-related and can be fatal; monitor serum theophylline levels closely; use with caution in patients with risk factors for reduced clearance (e.g., hepatic impairment, heart failure, elderly).
May cause hypertension, especially in patients with preeclampsia or hypertension. Use with caution in patients with sepsis, hepatic or renal impairment, coronary artery disease, or peripheral vascular disease. Avoid prolonged use. Monitor uterine tone and bleeding.
Narrow therapeutic index; severe toxicity can occur at levels >20 mcg/m L,Seizures and arrhythmias may occur without preceding symptoms,Variable clearance due to drug interactions, disease states, age, and smoking,Use with caution in peptic ulcer disease, seizure disorders, hyperthyroidism, and cardiac disease
Pregnancy (except for postpartum hemorrhage), hypertension, preeclampsia, eclampsia, coronary artery disease, peripheral vascular disease, Raynaud's phenomenon, sepsis, hypersensitivity to ergot alkaloids, concurrent use of potent CYP3A4 inhibitors.
Hypersensitivity to aminophylline or any component,Hypersensitivity to theophylline or ethylenediamine,Cardiac arrhythmias requiring immediate therapy (relative)
No known food interactions.
Avoid high-dose caffeine (coffee, tea, energy drinks, chocolate) as it may increase risk of side effects like nausea, anxiety, and tachycardia. Charcoal-broiled foods and a high-protein diet may increase theophylline clearance. Consistent dietary intake is recommended.
First trimester: Limited human data; animal studies show embryotoxicity and fetotoxicity at high doses due to uterotonic effects, but no structural malformations. Increased risk of spontaneous abortion from uterine hyperstimulation. Second trimester: Uterotonic effects may cause placental abruption, preterm labor, or fetal hypoxia. Third trimester: Contraindicated due to potent uterotonic activity; can cause uterine tetany, fetal distress, and stillbirth. Avoid during pregnancy unless for postpartum hemorrhage.
First trimester: Limited data; no increased risk of major malformations observed in human studies. Second and third trimesters: Risk of fetal tachycardia and jitteriness with high maternal doses; may cause transient neonatal tachycardia with chronic use. No documented teratogenicity.
Ergometrine and methylergonovine are excreted into breast milk in small amounts; M/P ratio estimated at 0.2-0.3. Milk concentrations are low (approximately 1-2% of maternal weight-adjusted dose). The American Academy of Pediatrics considers use compatible with breastfeeding, but may cause ergotism in infants (vomiting, diarrhea, seizures) with prolonged use. Short-term use for postpartum hemorrhage is generally acceptable.
Aminophylline/theophylline is excreted into breast milk with an M/P ratio of approximately 0.6-0.7. Infant exposure is low (about 1-10% of maternal dose). Irritability and insomnia reported rarely. Use with caution, monitor infant for signs of theophylline toxicity.
No dose adjustment required for pregnancy because drug is contraindicated during pregnancy due to uterotonic effects. In postpartum use (which is the approved indication), no pharmacokinetic changes necessitate dose adjustment; normal adult dosing applies (0.2 mg IM/IV for ergometrine, 0.2 mg IM for methylergonovine).
Pregnancy decreases theophylline clearance by approximately 20-30% during third trimester. Dosing adjustments may be required: monitor serum levels and adjust dose to maintain therapeutic levels. Postpartum clearance returns rapidly, requiring downward dose adjustment.
Administer intramuscularly or intravenously (slow push over 1 minute) for uterine atony; avoid in hypertension, preeclampsia, and sepsis. Store ampules protected from light; discard if discolored. Contraindicated in impaired hepatic or renal function.
Aminophylline is a bronchodilator that releases theophylline. Monitor serum theophylline levels (therapeutic range 5-15 mcg/m L). Avoid in patients with active peptic ulcer disease, seizure disorders, or hypersensitivity to xanthines. Caution in hepatic impairment, heart failure, and elderly due to reduced clearance. Drug interactions with cimetidine, ciprofloxacin, and macrolides increase theophylline levels.
This medication may cause nausea, vomiting, or headache.,Report severe abdominal pain, chest pain, or difficulty breathing immediately.,Avoid driving or operating machinery if dizziness occurs.,Do not use during pregnancy except for postpartum hemorrhage.,Inform your doctor if you have high blood pressure, heart disease, or are breastfeeding.
Do not exceed prescribed dose. Take exactly as directed.,Avoid caffeine-containing products (coffee, tea, cola, chocolate) as they may increase side effects.,Report symptoms of toxicity: nausea, vomiting, insomnia, rapid heart rate, palpitations, or seizures.,Do not crush or chew extended-release forms; take with food if gastric upset occurs.,Do not stop abruptly without consulting your healthcare provider.
"Coadministration of bromocriptine, a dopamine D2 receptor agonist with vasoconstrictive properties, and ergometrine, an ergot alkaloid that acts as a partial agonist at alpha-adrenergic and serotonin receptors, synergistically increases peripheral vasoconstriction. This additive effect can lead to severe hypertension, myocardial ischemia, cerebral vasospasm, and potentially life-threatening ergotism. Patients may present with headache, chest pain, altered mental status, or peripheral ischemia."
"Nylidrin, a beta-adrenergic agonist, and ergometrine, an ergot alkaloid with vasoconstrictive properties, exhibit a synergistic hypertensive effect. By stimulating beta-2 receptors, nylidrin may cause peripheral vasodilation and reflex tachycardia, while ergometrine induces vasoconstriction via alpha-adrenergic and serotonin receptor activation. This opposing mechanism can lead to unopposed vasoconstriction, potentially resulting in severe hypertension, myocardial ischemia, or stroke."
"Simvastatin, a HMG-CoA reductase inhibitor, may increase the serum concentration of ergometrine, an ergot alkaloid used for postpartum hemorrhage, by inhibiting its metabolism via CYP3A4. This can lead to enhanced vasoconstrictive effects of ergometrine, potentially causing severe hypertension, myocardial ischemia, or peripheral vasospasm. Concomitant use poses a risk of ergotism, manifesting as ischemic complications, and should be approached with caution."
"Concurrent administration of aminophylline, a xanthine derivative bronchodilator that is metabolized primarily by CYP1A2 and to a lesser extent CYP3A4, may reduce the clearance of ranolazine, an antianginal agent predominantly metabolized by CYP3A4 and to a lesser extent CYP2D6. Aminophylline can inhibit CYP3A4 activity, leading to increased ranolazine plasma concentrations, which elevates the risk of dose-dependent adverse effects such as QTc prolongation, dizziness, and syncope. This interaction is clinically significant and may necessitate dose adjustment or alternative therapy."
"Asunaprevir, a potent inhibitor of the drug transporter OATP1B1, can significantly decrease the serum concentration of aminophylline, a theophylline salt, likely by reducing its intestinal absorption or increasing its hepatic clearance. This interaction may lead to reduced therapeutic efficacy of aminophylline, potentially worsening respiratory symptoms in patients with asthma or COPD. Close monitoring and dose adjustment of aminophylline are recommended during coadministration with asunaprevir."
"Aminophylline, a bronchodilator, inhibits the metabolism of tibolone, a synthetic steroid hormone used for hormone replacement therapy, primarily through competitive inhibition of cytochrome P450 (CYP) 3A4 isoenzyme. This results in increased plasma concentrations of tibolone and its active metabolites, potentiating its hormonal effects and increasing the risk of adverse events such as thromboembolism, endometrial hyperplasia, or breast tenderness. Clinically, coadministration may require dose adjustments and careful monitoring for signs of estrogenic excess."
Explore head-to-head clinical comparisons of other medications in the same therapeutic classes.
Common clinical questions about Ergometrine / Methylergonovine vs AMINOPHYLLINE IN SODIUM CHLORIDE 0.45%, answered by our medical review team.
Ergometrine / Methylergonovine is a Ergot Alkaloid Uterotonic that works by Ergometrine and methylergonovine are ergot alkaloids that act as partial agonists at alpha-adrenergic, dopaminergic, and serotonergic (5-HT2) receptors. Their primary uterotonic effect is mediated by stimulation of 5-HT2 receptors in uterine smooth muscle, leading to sustained contractions and vasoconstriction.. AMINOPHYLLINE IN SODIUM CHLORIDE 0.45% is a Electrolyte that works by Aminophylline is a complex of theophylline and ethylenediamine, acting as a phosphodiesterase inhibitor, increasing intracellular c AMP levels; nonselective adenosine receptor antagonist; enhances cardiac inotropy, bronchodilation, and CNS stimulation.. They differ in pharmacokinetic profiles, FDA-approved indications, and side effect profiles.
Potency comparisons between Ergometrine / Methylergonovine and AMINOPHYLLINE IN SODIUM CHLORIDE 0.45% depend on the specific clinical indication. These are agents from distinct pharmacological classes and are not directly interchangeable by dose. A physician or clinical pharmacist should guide any therapeutic switching decisions.
The standard adult dose of Ergometrine / Methylergonovine is: 0.2 mg intramuscularly or intravenously, repeated every 2-4 hours as needed, up to 5 doses total. Maximum single dose: 0.5 mg. Maximum total dose: 1 mg.. The standard adult dose of AMINOPHYLLINE IN SODIUM CHLORIDE 0.45% is: Loading dose: 5-6 mg/kg IV over 20-30 minutes, then continuous infusion: 0.5-0.7 mg/kg/hour IV.. Dosing should always be individualized based on indication, renal and hepatic function, age, and other patient factors.
No direct drug-drug interaction has been formally documented between Ergometrine / Methylergonovine and AMINOPHYLLINE IN SODIUM CHLORIDE 0.45% in current clinical databases. However, individual patient risk factors including other medications, organ function, and comorbidities should always be evaluated by a qualified healthcare provider.
The maternal-fetal safety profiles differ. Ergometrine / Methylergonovine is classified as Category C. First trimester: Limited human data; animal studies show embryotoxicity and fetotoxicity at high doses due to uterotonic effects, but no structural malformations. Increased risk of. AMINOPHYLLINE IN SODIUM CHLORIDE 0.45% is classified as Category A/B. First trimester: Limited data; no increased risk of major malformations observed in human studies. Second and third trimesters: Risk of fetal tachycardia and jitteriness with high . Always consult a maternal-fetal medicine specialist before taking either drug during pregnancy or lactation.