Name: Phenylephrine (NeosynephrineR)
Classification: sympathomimetic, vasopressor
  • stimulates alpha adrenergic receptors resulting in
    • vasoconstriction
    • decreased heart rate 
    • increased peripheral resistance
  • used to increase blood pressure
  • Bolus dose
    • hypotension or shock:  0.1-0.5mg as slow IV direct injection q10-15min (or 1-10mg IM/SC q1-2hours)
    • PSVT:  0.5-1mg as rapid direct IV injection q60-90 seconds
  • IV infusion: 
    • 0.04-0.18mg/min (40-180 mcg/min), titrated to effect 
Administration: IV Infusion:
100 mg/250ml D5W or NS
  • hypovolemia, hypoxemia and acidosis should be corrected concurrently with initiation of therapy
  • should be weaned off
Adverse Effects:
  • bradycardia 
  • arrhythmias
  • increased myocardial oxygen consumption; avoid in patients with left ventricular dysfunction
  • peripheral or mesenteric ischemia
  • renal failure
  • headache
  • restlessness or excitability
  • extravasation of drug will cause tissue necrosis and ulceration (treat with 5-15mg phentolamine in NS - see phentolamine monograph)
Drug Interactions:
  • phenylephrine + atropine = increased BP and tachycardia
  • phenylephrine + halogenated anaesthetics = increased cardiac irritability
  • phenylephrine + alpha blocking agents = blockade of vasopressor effect
  • phenylphrine + other sympathomimetics = increased risk of toxicity
Monitoring Therapy:
  • BP
  • HR, ECG
  • urine output, BUN, creatinine
  • cardiac index
  • SVRI
  • arterial lactate
  • PWP
  • changes in skin colour or tempurature
  • chest pain
CCTC Protocol:
  • May be administered by IV infusion by an approved nurse in CCTC.
  • May be administered IV direct by an approved nurse in CCTC.
  • May be titrated by an approved nurse in CCTC.
  • Must be administered via a central line.
  • Continuous infusion must be administered via an infusion pump.
  • Should not be infused via the proximal injectate port (blue) of the Swan Ganz catheter.
  • Patient requires placement of an arterial line to monitor BP.

Lynne Kelly, Pharmacist, CCTC
Brenda Morgan, Clinical Nurse Specialist, CCTC
Last Update: March 3, 2017

Reviewed: January 12, 2017

Revised: March 3, 2017


LHSCHealth Professionals

Last Updated March 3, 2017 | © 2007, LHSC, London Ontario Canada