The Food and Drug Administration (FDA) has approved Rezipres® (ephedrine hydrochloride injection) for the treatment of clinically important hypotension occurring in the setting of anesthesia.

Rezipres is a sulfite-free formulation of ephedrine hydrochloride. It is supplied as single-dose ampules containing 47mg/mL solution of ephedrine hydrochloride (each mL equivalent to 38mg ephedrine base), 9.4mg/mL solution of ephedrine hydrochloride (each mL equivalent to 7.7mg ephedrine base), and 4.7mg/mL solution of ephedrine hydrochloride (each mL equivalent to 3.8mg ephedrine base).

Rezipres 47mg/mL must be diluted before administration, while the 9.4mg/mL can either be used as provided or it can be diluted. Rezipres 4.7mg/mL is a premixed formulation and should not be diluted prior to use.

Ephedrine hydrochloride, a sympathomimetic amine, is an alpha- and beta-adrenergic agonist and a norepinephrine-releasing agent. Pressor effects by direct alpha- and beta-adrenergic receptor activation are mediated by increases in arterial pressures, cardiac output, and peripheral resistance. Ephedrine stimulates heart rate and cardiac output and variably increases peripheral resistance, resulting in increased blood pressure. 

“We are excited to see the approval of Rezipres, which is now our second FDA-approved ready-to-use hospital injectable product. We believe ready-to-use injectable products provide a compelling benefit to hospitals and reduce the need for hospitals to rely on unapproved compounded products,” said Sean Brynjelsen, CEO of Eton Pharmaceuticals. “This innovative sulfite-free formulation has been successfully sold in Europe for years, and we are excited to make it available to US patients shortly.”


  1. Eton Pharmaceuticals announces FDA approval of Rezipres® (ephedrine hydrochloride injection). [press release]. Deer Park, IL: Eton Pharmaceuticals, Inc.; June 15, 2021. 
  2. Rezipres [package insert]. Deer Park, IL; Eton Pharmaceuticals, Inc.; 2021.