Clinical Study to Investigate the Pharmacokinetics of Multiple Repeated Doses of Intranasal Naloxone

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)