Naloxone, a fast-acting mu-opioid antagonist, is a treatment commonly used in reversing opioid overdose. Naloxone is available in multiple formulations, including for injection intravenously, intramuscularly or subcutaneously, and more recently as a spray administered intranasally (IN). The IN naloxone formulation, which was approved in 2015, is of particular interest as there is a need for naloxone formulations for community use by caregivers and first responders/law enforcement who do not have medical training. It is critical to administer naloxone as quickly as possible to prevent irreversible brain damage and death.~The U.S. Food and Drug Administration (FDA), Center for Drug Evaluation and Research (CDER), Division of Applied Regulatory Science (DARS) has conducted modeling and simulation, evaluating how many doses of IN naloxone may be needed to reverse opioid-induced respiratory depression from fentanyl and fentanyl derivates under a range of overdose scenarios. These analyses have suggested that more than two doses of IN naloxone are sometimes required to reverse the effects of highly potent opioids (e.g., certain fentanyl derivatives). Experience with intranasal formulations for other products has shown that repeat administration of doses given in close proximity to the same nostril can influence drug exposure due to run-off from the application site, limited absorption, or other factors. While the pharmacokinetics of IN naloxone have been determined following administration of a 4 mg dose in each nostril concurrently, the pharmacokinetics have not been determined following multiple doses according to the FDA product label:~Administer a single spray intranasally into one nostril.~Administer additional doses using a new nasal spray with each dose, if the patient does not respond or responds and then relapses into respiratory depression, additional doses may be given every 2 to 3 minutes until emergency medical assistance arrives.~This involves a 2-3 minute delay between each dose and re-administering to a previously dosed nostril starting with the 3rd dose, which may result in a less than dose-proportional increase in naloxone plasma concentration and/or delayed increase in naloxone exposure compared to the first 2 doses. Obtaining data with repeat dosing will inform if and how fast naloxone plasma concentrations can be reached to be able to reverse highly-potent opioid overdoses.~This study will be a randomized, unblinded, three-way crossover study to determine naloxone plasma concentration after administration of multiple doses:~A. Four 4 mg IN naloxone doses (1 dose every 2.5 minutes) B. Four 4 mg IN naloxone doses (2 doses every 2.5 minutes) C. Two 4 mg IN naloxone doses (1 dose every 2.5 minutes)~The above 3 treatments will be evaluated in a randomized order over 3 treatment periods. Healthy subjects will be randomized to one of six treatment sequences (i.e., ABC, ACB, BAC, BCA, CAB, CBA). Subjects will report to the study site for screening from Days -28 to -2 and then will return to the site on Day -1 for baseline assessments and check-in. After check-in (Day -1), subjects will receive dosing for the 3 respective treatment periods on Days 1, 4 and 7. There will be two days of washout between each treatment period. Participants will be confined in the study clinic from Day -1 until the morning of Day 8. On dosing days, dosing will occur as per the treatment description and pharmacokinetic (PK) assessments will occur at 16 different time points.
Intranasal (IN) naloxone is available as 2 mg or 4 mg dose with the indication to re-administer additional doses every 2 to 3 minutes (using alternating nostrils) if needed until emergency medical assistance arrives. The 4 mg dose is distributed in packages of two nasal sprays (1 dose per nasal spray), but additional doses can be administered if needed and available.~While the pharmacokinetics of IN naloxone have been determined following administration of a 4 mg dose in each nostril concurrently, the pharmacokinetics have not been determined following multiple doses when there is a 2-3 minute delay between doses and when doses are re-administered to the same nostril.~Obtaining data with repeat dosing will inform if and how fast naloxone plasma concentrations can be reached to be able to reverse highly-potent opioid overdoses. This study will be a randomized, unblinded, three-way crossover study to determine naloxone plasma concentration after administration of multiple doses:~A. Four 4 mg IN naloxone doses (1 dose every 2.5 minutes) B. Four 4 mg IN naloxone doses (2 doses every 2.5 minutes) C. Two 4 mg IN naloxone doses (1 dose every 2.5 minutes)