CLINICAL STUDIES — FDA approval of the 1-mg formulation of neffy was based on the results of a pharmacologic study (summarized in the package insert) that included 21 children ≥4 years old who weighed 15 to <30 kg. Geometric mean plasma epinephrine concentrations in the children after a 1-mg dose were higher than those in a reference group of adults after a 2-mg dose. 

ADVERSE EFFECTS — Adverse effects of the 1-mg dose included nasal and upper respiratory tract congestion, dry throat, nasal dryness, and paresthesia. The nasal spray solution contains sodium metabisulfite, which could cause a hypersensitivity reaction in patients with a sulfite allergy, but a history of sulfite sensitivity should not deter emergency use of the product. 

DOSAGE, ADMINISTRATION, AND COST — The recommended dosage of neffy in children ≥4 years old who weigh 15 to <30 kg is one 1-mg spray administered into one nostril. If symptoms have not improved after 5 minutes, a second spray can be administered into the same nostril using a new device. The nasal spray should be stored at room temperature, but excursions up to 50° C (122° F) are permitted. At temperatures below -15° C (5° F), the solution freezes and the device cannot deliver epinephrine. The shelf life of neffy 1 mg is 24 months (the 2-mg formulation has a shelf life of 30 months). 

The 1-mg formulation of neffy is expected to be available in May 2025. According to the manufacturer, the out-of-pocket cost for two neffy nasal spray devices should not exceed $25 for most patients with commercial insurance.2