NEW YORK (Reuters Health)- Extensive animal research and early human studies suggest that sublingual epinephrine may be an alternative to epinephrine self-injection for out-of-hospital first-aid treatment of anaphylaxis.
Dr. Xiaochen Gu and colleagues, from the University of Manitoba, Winnipeg, Canada, examined the rate and extent of sublingual absorption of epinephrine in a prospective, randomized, four-way crossover study in rabbits.
Animals received 2.5 mg or 10 mg epinephrine tablets sublingually, 0.03 mg epinephrine by intramuscular (IM) injection, or 0.1 mL saline injection. They obtained blood samples at baseline and at different time points up to 180 minutes after epinephrine administration to determine the rate of absorption.
Sublingual epinephrine tablet administration was well tolerated and resulted in high, rapidly achieved peak epinephrine plasma concentrations similar to those achieved after IM injection, Dr. Gu explained in a telephone interview with Reuters Health.
The 2.5 mg and 10 mg sublingual epinephrine dose reached peak effectiveness at 20.8 minutes and 21.7 minutes, respectively, while the epinephrine injection reached peak effectiveness at 15.8 minutes.
"These results prove that epinephrine can be absorbed through the sublingual route," Dr. Gu said. "It works fine and could be an alternative route of administration for anaphylaxis, especially for children because you have to use needles otherwise."
Dr. Gu said his team conducted some preliminary human trials a couple years go, using powdered epinephrine. "In those studies we got some absorption, but because the dose we used was a bit low, we didn't get as dramatic a result as we expected, so we will increase the dose in human studies in the future."
The findings were presented in New York City this week during the 58th Annual Meeting of the American Academy of Allergy, Asthma & Immunology.