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Intravenous Phenylephrine

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Intravenous Phenylephrine, Intravenous Neo-Synephrine, Phenylephrine, Neo-Synephrine, Phenylephrine Push Dose Pressor

  • See Also
  1. Septic Shock
  2. Intranasal Phenylephrine
  3. See Push Dose Pressor
  1. Emergency Resuscitation for cardiovascular collapse while performing other interventions
    1. Example: Septic Shock refractory to fluid Resuscitation, temporizing while obtaining central access
    2. Can be used via peripheral IV for hours until central access is available for other Vasopressors (e.g. Norepinephrine)
  2. Conscious Sedation
    1. Commonly used by anesthesiology for Hypotension secondary to Propofol and other agents
  • Contraindications
  1. Severe Coronary Artery Disease (or other severe Cardiomyopathy)
  • Mechanism
  • Intravenous
  1. Direct selective alpha-Adrenergic Agonist
  2. Push Dose Pressor (Bolus Phenylephrine)
    1. Vasopressor without direct inotropic (contractility) or chronotropic (Heart Rate) activity
  3. Increases cardiac perfusion via Vasoconstriction and secondary increase in venous return
  • Pharmacokinetics
  • Intravenous
  1. Onset: 1 minute
  2. Duration: 10-20 minutes
  • Adverse Effects
  • Intravenous
  1. Local infiltration effects (extravasation)
    1. Risk of tissue ischemia, necrosis and gangrene
    2. Less local toxicity to tissue and vascular structures compared with other pressors
  2. Reflex Bradycardia
    1. Unlikely to occur during cardiovascular collapse in which adrenergic response is expected to be strong
    2. Baroreceptor reflex to increasing BP is typically outweighed by a stronger adrenergic response
  • Preparation
  • Intravenous
  1. See Push Dose Pressor
  2. Dilute 1 ml (10 mg) from Phenylephrine vial (10 mg/ml) in Normal Saline 100 ml bag
  3. Resulting solution: Phenylephrine 100 mcg/ml
  4. Draw solution into labeled syringe for use as Push Dose Pressor
  • Dosing
  • Adult
  1. Phenylephrine IV bolus
    1. Bolus (100 mcg/ml) 50 to 200 mcg (0.5 to 2 ml) IV bolus as needed every 10 to 15 min
    2. May initially be needed every 2-5 minutes in severe Hypotension
  2. Phenylephrine IV Infusion
    1. Prepare 20 mg Phenylephrine in 250 ml D5W (80 mcg/L)
    2. Start 100 to 180 mcg/min (75 to 135 ml/h)
    3. Maintain typically at 40 to 60 mcg/min
  • Dosing
  • Child (off label)
  1. Phenylephrine IV bolus
    1. Bolus (100 mcg/ml) 5 to 20 mcg/kg IV bolus as needed every 10 to 15 min
  2. Phenylephrine IV Infusion
    1. Prepare 20 mg Phenylephrine in 250 ml D5W (80 mcg/L)
    2. Infuse 0.1 to 0.5 mcg/kg/min IV, titrating to target Blood Pressure and perfusion
  • Resources
  1. EM-Crit Blog (Scott Weingart)
    1. http://emcrit.org/podcasts/bolus-dose-pressors/
    2. http://emcrit/wp-content/uploads/push-dose-pressors.pdf
  2. Phenylephrine Injection Solution (DailyMed)
    1. https://dailymed.nlm.nih.gov/dailymed/lookup.cfm?setid=c3f358dd-4a36-4808-9943-e01f88604be5
  • References
  1. Hamilton (2020) Tarascon Pharmacopoeia, Jones and Bartlett, Boston
  2. Mattu and Weingart in Majoewsky (2013) EM:Rap 13(4): 9-10