Epinephrine-induced vasospasm reversed by phentolamine digital block

A case of profound digital vasoconstriction caused by the accidental injection of epinephrine from a commercial bee sting kit is reported. One hour later the patient had a cold, painful, blanched finger. A digital block using a 2-mg dose of phentolamine mixed with 2% lidocaine was performed. Thirty minutes after treatment, the finger was pink and warm. The patient reported a marked decrease in pain. Reexamination 12 hours later showed only mild tenderness at the fingertip. No tissue necrosis occurred. One month after injection, there were no apparent sequelae. Although the use of alpha-adrenergic blocking agents by regional infiltration to treat accidental infusion or extravasation of epinephrine has been suggested, no reports of this technique are found in the emergency medicine literature. The mechanism of digital vasoconstriction and the action of phentolamine are discussed.