The growing crisis of the abuse of illicit and prescription opioids in humans has led to accidental exposures in pets and working dogs.1-4 In humans, a commercial intranasal naloxone hydrochloride atomizer is available to treat opioid overdoses and may be purchased without a prescription.5 There is a growing interest in the use of such atomizers in veterinary patients, particularly for emergency stabilization prior to transporting a patient to a veterinary facility for care.3,4
This study compared IV naloxone with intranasal naloxone delivered by a commercially available atomizer in healthy dogs. Time to reach peak plasma levels, maximum concentration, and naloxone half-life were measured and calculated. The intranasal route rapidly achieved clinically useful plasma levels in healthy medium-sized dogs. Naloxone was detectable in plasma 2.3 ± 1.4 minutes after intranasal administration; mean time to maximum concentration in plasma was 22.5 ± 8.2 minutes. Naloxone half-life was similar for both routes of administration (IV, 37 ± 6.7 minutes; intranasal, 47.4 ± 6.7 minutes). It is unclear if nasal conformation (eg, brachycephaly, dolichocephaly) affects intranasal absorption.
Reported adverse effects of naloxone include excitability, vomiting, and tachycardia; however, there were no notable changes in behavior, heart rate, or respiratory rate following naloxone administration by either route in this study.