Section 13 · Monograph
Phenylephrine
Reviewed Nov 2026FDA label
Neo-SynephrineVasopressor
- Forms
- IV: 10mg/mL vial; premixed bags
- Dose
- Infusion typically 0.5-6mcg/kg/min (or 20-200mcg/min) titrated to MAP/CPP; bolus 50-250mcg
- MOA
- Selective α1 agonism
Indications
- Treatment of clinically important hypotension resulting primarily from vasodilation in the setting of anesthesiaFDA-labeled
Off-Label Uses
- Neurogenic hypotensionOff-label
- MAP or CPP augmentation in acute ischemic stroke or SAH vasospasm per protocolOff-label
Mechanism of Action
- Selective alpha-1 adrenergic agonist producing arterial and venous vasoconstriction without direct cardiac stimulation
Full Dosing
Adult / usual
- Bolus 50-250mcg IV as needed
- Infusion typically 0.5-6mcg/kg/min (or 20-200mcg/min), titrated to MAP or CPP goal
- Dilute concentrated vials before use
Contraindications
- Severe hypertension or ventricular tachycardia
- Hypersensitivity to phenylephrine or sulfites (some products)
Drug Interactions
- MAOIs and tricyclic antidepressants potentiate pressor effects
- Alpha-blockers antagonize the effect
- Oxytocics increase hypertension risk
Adverse Effects
- Reflex bradycardia
- Severe hypertension
- Decreased cardiac output in poor ventricular function
- Extravasation with tissue necrosis
Monitoring Parameters
- Continuous blood pressure and heart rate
- Infusion site
- Perfusion and urine output
Pregnancy & Lactation
- Used in obstetric anesthesia; limited other data
- Unknown whether present in milk