III. Dosing: Adults

  1. Hypertensive Crisis in Pheochromocytoma
    1. Give 5 mg IV/IM for one dose
    2. Results in profound Blood Pressure drop (e.g. 60/25 mmHg decrease in BP)
  2. Vasopressor Extravasation (e.g. Norepinephrine) - Not FDA approved
    1. Prepare 5-10 mg in 10 ml Normal Saline
    2. Inject 1 ml SC around extravasation site within 12 hours of extravasation
    3. In adults may repeat dose up to a total of 5 ml injected around extravasation site

IV. Dosing: Children

  1. Hypertensive Crisis in Pheochromocytoma
    1. Give 0.05 to 0.1 mg/kg (up to 5 mg) IV/IM for one dose
    2. Results in profound Blood Pressure drop (e.g. 60/25 mmHg decrease in BP)
  2. Vasopressor Extravasation (e.g. Norepinephrine) - Not FDA approved
    1. Prepare 5 mg in 10 ml Normal Saline
    2. Inject 1 ml SC around extravasation site within 12 hours of extravasation

V. Mechanism

  1. Synthetic imidazoline acts as a competitive Alpha Adrenergic Antagonist at alpha-1 and alpha-2 receptors resulting in vasodilation
  2. May block 5-HT receptors
  3. May stimulate Histamine release from Mast Cells

VI. Adverse Effects

  1. Hypotension
  2. Generalized Weakness

VII. Safety

  1. Pregnancy Category C
  2. Unknown Safety in Lactation

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Ontology: Phentolamine (C0031448)

Definition (NCI) A synthetic imidazoline with alpha-adrenergic antagonist activity. As a competitive alpha-adrenergic antagonist, phentolamine binds to alpha-1 and alpha-2 receptors, resulting in a decrease in peripheral vascular resistance and vasodilatation. This agent also may block 5-hydroxytryptamine (5-HT) receptors and stimulate release of histamine from mast cells.
Definition (MSH) A nonselective alpha-adrenergic antagonist. It is used in the treatment of hypertension and hypertensive emergencies, pheochromocytoma, vasospasm of RAYNAUD DISEASE and frostbite, clonidine withdrawal syndrome, impotence, and peripheral vascular disease.
Definition (CSP) nonselective alpha-adrenergic antagonist.
Concepts Pharmacologic Substance (T121) , Organic Chemical (T109)
MSH D010646
SnomedCT 372863003, 82165003
English Fentolamin, Phenol, 3-(((4,5-dihydro-1H-imidazol-2-yl)methyl)(4-methylphenyl)amino)-, 2-[N-p'-Tolyl-N-(m'-hydroxyphenyl)aminomethyl]imidazoline, phentolamine (medication), alpha blockers phentolamine, Phentolamine [Chemical/Ingredient], fentolamin, Phentolamine, PHENTOLAMINE, phentolamine, Phentolamine (product), Phentolamine (substance), PTM
Swedish Fentolamin
Czech fentolamin
Finnish Fentolamiini
Russian FENTOLAMIN, ФЕНТОЛАМИН
Japanese メシル酸フェントラミン, レギチーン, フェントラミンメシル酸塩, フェントラミンシアル酸塩, フェントールアミン, フェントラミン, レギチン, ロギチン, 塩酸フェントラミン, フェントラミン塩酸塩, シアル酸フェントラミン
Croatian FENTOLAMIN
Polish Fentolamina, Regityna
Spanish fentolamina (producto), fentolamina (sustancia), fentolamina, Fentolamina
French Phentolamine
German Fentolamin, Phentolamin
Italian Fentolamina
Portuguese Fentolamina