UMEM Educational Pearls

Category: Toxicology

Title: Phentolamine Use in Hypertensive Crisis

Keywords: phentolamine, tyramine, pheochromocytoma (PubMed Search)

Posted: 2/12/2009 by Bryan Hayes, PharmD (Updated: 1/21/2022)
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You have a 44 y/o female patient with an arterial line monitoring her blood pressure which is reading 302/156 mm Hg.  Her heart rate is 140 bpm.  Her history reveals she is taking a monoamine oxidase inhibitor (MAOI) and has inadvertantly ingested tyramine at her friend's cheese/wine party.   What do you do?

  • Conditions producing hypertensive crisis from catecholamine surges (phenylephrine overdose, cocaine, tyramine interactions, pheochromocytoma) can be treated with phentolamine
  • Phentolamine is a nonspecifc alpha blocking agent which produces peripheral vasodilation with a resultant fall in blood pressure in most patients.
  • Other uses include extravasation of some vasopressors (e.g. norepineprhine)
  • May see an increase in HR after administration (once alpha blockade is established, beta-blocker can be administered)
  • Dose: 5-15 mg IV/IM
  • Duration: 30-45 minutes