EMERPHED
Clinical safety rating: caution
Comprehensive clinical and safety monograph for EMERPHED (EMERPHED).
EMERPHED is a combination of ephedrine and phenylephrine. Ephedrine is a sympathomimetic amine that acts directly on alpha and beta adrenergic receptors and indirectly by releasing norepinephrine from nerve endings, causing vasoconstriction, bronchodilation, and increased heart rate and blood pressure. Phenylephrine is a selective alpha-1 adrenergic receptor agonist causing vasoconstriction and increased blood pressure.
| Metabolism | Ephedrine is partially metabolized by hepatic enzymes including CYP2D6 and monoamine oxidase (MAO). Phenylephrine undergoes first-pass metabolism in the gut wall and liver via sulfation and oxidation, predominantly by MAO and to a lesser extent by CYP2D6. |
| Excretion | Renal excretion of unchanged drug (~30-50%) and metabolites; minor biliary/fecal elimination (<10%). |
| Half-life | Terminal elimination half-life: 3-6 hours (prolonged in renal impairment: up to 15 hours). |
| Protein binding | ~50% bound primarily to albumin and alpha-1-acid glycoprotein. |
| Volume of Distribution | 2.5-4.0 L/kg, indicating extensive tissue distribution. |
| Bioavailability | Oral: ~40% due to first-pass metabolism; IM: 70-90%; IV: 100%. |
| Onset of Action | Oral: 15-30 minutes. Intramuscular: 5-10 minutes. Intravenous: Immediate (<1 minute). |
| Duration of Action | Oral: 3-6 hours. IV: 1-3 hours (duration dose-dependent due to tachyphylaxis). |
| Molecular Weight | 165.23 |
Adults: 1-2 capsules (25-50 mg ephedrine sulfate) orally every 3-4 hours as needed, not to exceed 150 mg in 24 hours.
| Dosage form | SOLUTION |
| Renal impairment | GFR 30-60 mL/min: Reduce dose by 50%; GFR <30 mL/min: Avoid use or extend interval to every 8-12 hours. |
| Liver impairment | Child-Pugh A: No adjustment; Child-Pugh B: Reduce dose by 50%; Child-Pugh C: Avoid use. |
| Pediatric use | Children 2-12 years: 0.5-1 mg/kg/dose orally every 4-6 hours, maximum 5 mg/kg/day or 150 mg/day. |
| Geriatric use | Elderly: Start at lowest effective dose (12.5-25 mg) every 6 hours due to increased sensitivity and risk of CNS stimulation, hypertension, and urinary retention. |
| 1st trimester | Avoid due to potential teratogenicity from ephedrine; case reports of malformations. |
| 2nd trimester | Use only if clearly needed; may reduce uterine blood flow. |
| 3rd trimester | Avoid near term; can cause maternal hypertension and fetal tachycardia. |
Clinical note
Comprehensive clinical and safety monograph for EMERPHED (EMERPHED).
| Placental transfer | Crosses placenta rapidly; detected in fetal circulation at 70-100% of maternal levels. |
| Breastfeeding | Ephedrine excreted into breast milk in low amounts; limited data. Monitor infant for irritability and insomnia. |
| Lactation Rating |
■ FDA Black Box Warning
No FDA black box warnings.
| Serious Effects |
Hypersensitivity to ephedrine or any componentSevere coronary artery diseaseUncontrolled hypertensionUse with monoamine oxidase inhibitors (MAOIs)Angle-closure glaucoma
| Precautions | Cardiovascular effects: May cause hypertension, tachycardia, arrhythmias, Increased heart rate and contractility in patients with coronary artery disease, Potential for hypertensive crisis with MAO inhibitors, Pheochromocytoma: may precipitate hypertensive crisis, Hyperthyroidism: may exacerbate symptoms, Diabetes mellitus: may increase blood glucose, Prostatic hypertrophy: may cause urinary retention |
| Food/Dietary | Avoid caffeine-containing foods and beverages (coffee, tea, cola, chocolate) as they may increase stimulant effects. Also avoid tyramine-rich foods (aged cheeses, cured meats, soy products) if taking with MAOIs. |
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| L3 |
| Teratogenic Risk | First trimester: Avoid due to potential for ephedrine-induced vasoconstriction reducing uteroplacental blood flow and possible neural tube defects (limited data). Second and third trimesters: Ephedrine may cause fetal tachycardia, increased risk of intraventricular hemorrhage if used near delivery. Risk of preterm labor with prolonged use. Overall, FDA Category C. |
| Fetal Monitoring | Monitor maternal blood pressure, heart rate, and signs of uterine hyperstimulation. Fetal: Heart rate monitoring (tachycardia may occur). Assess for signs of fetal distress or preterm labor. |
| Fertility Effects | No documented adverse effects on fertility in humans. Animal studies show no significant reproductive impairment. |
| Clinical Pearls | Emerphed (ephedrine) is a sympathomimetic amine used for hypotension. Monitor blood pressure and heart rate closely; avoid in patients with severe hypertension, tachyarrhythmias, or narrow-angle glaucoma. Tachyphylaxis can occur with repeated use. Use with caution in patients with benign prostatic hyperplasia as it may precipitate urinary retention. |
| Patient Advice | Take this medication exactly as prescribed; do not exceed the recommended dose. · Report symptoms of chest pain, fast or irregular heartbeat, severe headache, or shortness of breath immediately. · Avoid taking with other stimulants, decongestants, or diet aids that contain ephedrine or pseudoephedrine. · Inform your doctor if you have high blood pressure, heart disease, diabetes, or an overactive thyroid. · This medication may cause dizziness or blurred vision; avoid driving or operating machinery until you know how it affects you. |