Vasopressors and inotropes
Phenylephrine (Neo-Synephrine) drip
Neo-Synephrine
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Dosing
| Start | 10–35 mcg/min |
|---|---|
| Titrate | By blood pressure, every few minutes |
| Maximum | 200 mcg/min |
| Common bags | 50 mg in 250 mL (200 mcg/mL); 20 mg in 250 mL (80 mcg/mL); 100 mg in 250 mL (400 mcg/mL) |
| Dose units | mcg/min, mcg/kg/min |
Line and administration
- Central line preferred; peripheral is acceptable short term in a large proximal arm vein with frequent site checks
- Extravasation: stop, aspirate, phentolamine 5–10 mg in 10–15 mL saline injected into the area
Watch for
- Reflex bradycardia
- Lower cardiac output: a poor choice in pump failure
- Useful in LVOT obstruction
Phenylephrine: full drug monographIndications, mechanism, pharmacokinetics, cautions and every dose the app lists.
In the one-pagers
- Vasopressors and InotropesReceptors and effects: Phenylephrine: α1 only: ↓ reflex / ↔ / ↑↑
- Endocarditis and Valve EmergenciesValve emergencies: Critical AS: Syncope, HF; AF or low preload crashes it: Phenylephrine; cardiovert AF; TAVR or BAV
- CEN: Genitourinary, Gynecologic and Early-Pregnancy EmergenciesThe acute scrotum and penis: Ischemic priapism: Over 4 h, rigid, painful; injections, sickle cell, drugs: Aspiration and phenylephrine 100 to 500 mcg every 3 to 5 min; BP and HR
- Right Heart Failure and Pulmonary HypertensionManagement priorities: Phenylephrine: Avoid alone: Raises PVR
- After Cardiac SurgeryValves, TAVR, off-pump and minimally invasive surgery: Mitral repair with SAM: About 5–10%: volume, phenylephrine, beta-blocker
- Airway and RSIThe physiologically difficult airway: resuscitate first: Fluids alone do not prevent collapse: in PREPARE II (Russell, JAMA 2022; 1,065 patients) a 500 mL bolus at induction did not reduce cardiovascular collapse (21.0% vs 18.2%). For most patients the more reliable step is a vasopressor started before induction. Push-dose phenylephrine (50–200 mcg) or epinephrine (10–20 mcg) covers the gap; label
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For education and exam preparation only. Follow your institution’s protocols. Study aid: check every dose against the order, the bag label, your pump library and your institution's protocol.