Ultra-potent opioids are commonly used to immobilize zoological species and the Association of Zoos and Aquariums requires all accredited zoos to have an accidental drug administration protocol.3 Thirty zoological institutions, representing a wide size range of veterinary programs, were asked to provide their accidental drug administration protocol to evaluate the methods recommended to treat accidental exposure to injectable opioid agents, such as etorphine, carfentanil, and thiafentanil. Nine zoos provided their accidental drug administration protocol for evaluation. Eight protocols instructed persons to attempt to place an intravenous catheter. Varying doses of naloxone (NarcanTM, Endo Pharmaceuticals, Inc., Chadds Ford, Pennsylvania 19317, USA), ranging from 2 mg to 12 mg administered intravenously were recommended by the protocols. All protocols stated to give naloxone intramuscularly if intravenous access could not be achieved. No protocol suggested the use of intranasal naloxone for the accidental exposure to ultra-potent opioids.
Two studies have shown concentrated 1 mg/ml naloxone given intranasally to people is as effective as giving the same dose intramuscularly or intravenously.2,4 Another study demonstrated that 83% of individuals suspected of opioid overdose responded to intranasal administration of naloxone without the need for supplementation of intravenous naloxone.1 Intranasal administration of naloxone is achieved via a mucosal atomization device (MADTM, Wolfe Tory Medical, Inc., Salt Lake City, Utah 84107, USA).2 Intranasal administration of naloxone appears to be as effective as intravenous naloxone and should be considered as an alternative method to provide emergency relief in the zoo or field settings to individuals not trained in intravenous administration of medications to humans.
The authors would like to thank the institutions that provided their accidental drug administration protocols for this survey and Dr. Fred Wenger for his insight into the use of naloxone in the Emergency Department at the UT Medical Center.
1. Barton ED, CB Colwell, T Wolfe, D Fosnocht, C Gravitz, T Bryan, W Dunn, J Benson, J Bailey. Efficacy of intranasal naloxone as a needless alternative for treatment of opioid overdose in the prehospital setting. J Emerg Med. 2005;29: 265–271.
2. Barton ED, J Ramos, C Colwell, J Benson, J Bailey, W Dunn. Intranasal administration of naloxone by paramedics. Prehosp Emerg Care. 2002;6:54–58.
3. Haigh JC. Opioids in zoological medicine. J Zoo Wildl Med. 1991;21:391–413.
4. Kerr D, A Kelly, P Dietze, D Jolley, B Barger. Randomized controlled trial comparing the effectiveness and safety of intranasal and intramuscular naloxone for the treatment of suspected heroin overdose. Addiction. 2009;104:2067–2074.