Pharmacokinetics and pharmacodynamics of potential intranasal alternative to intramuscular epinephrine
Published online October 10, 2024
Anaphylaxis is a severe, potentially fatal allergic reaction that should be treated immediately with epinephrine. Individuals who are at risk of anaphylaxis are often given an auto-injector that will allow them (or a friend or family member) to administer epinephrine to the thigh muscle if they are experiencing anaphylaxis. However, many patients hesitate to use the auto-injector because they are afraid of needles or worry it will cause them harm. An intranasal epinephrine product is under development as an alternative method of epinephrine self-administration for the treatment of anaphylaxis.
In a recent study published in The Journal of Allergy and Clinical Immunology: In Practice, Greenhawt and Lieberman et al. report the results of a compilation of 4 studies that compared the pharmacokinetics (e.g., how much and how fast epinephrine reached the blood stream) and pharmacodynamics (e.g., effects on heart rate and blood pressure) of an epinephrine nasal spray (ENS) with an intramuscular auto-injector in healthy subjects. In one study period, each participant received a full dose (2 sprays) of ENS in the same nostril; in another study period, they received a full dose of ENS sprayed in opposite nostrils; and in another separate study period, they received epinephrine in the thigh muscle by an auto-injector. Blood samples, heart rate, and blood pressure were collected at multiple timepoints starting at 1 minute after the dose up until 360 minutes after the dose to compare the epinephrine pharmacokinetics and pharmacodynamics.
The ENS sprayed in either the same nostril or opposite nostrils quickly increased epinephrine in the blood, and the level of epinephrine was overall higher than with the intramuscular epinephrine. The maximum amount of epinephrine in the blood was reached within 20 minutes with all 3 treatments. Epinephrine stayed in the blood longer with ENS than with intramuscular injection. The effect of treatment on heart rate and blood pressure was minimal and similar among all 3 treatments. The level of epinephrine in the blood achieved by ENS was as high and fast as injection in the thigh, with similar minimal effects on heart rate and blood pressure. This suggests ENS may be a suitable alternative option to intramuscular epinephrine delivery.
The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.
Full Article