Sign in to Print/View PDF


Antidote, Opiate Antagonist (Systemic Drug)

Prescriber Highlights

Injectable opiate antagonist

Reversal effect may last for a shorter time than opioid effect

Uses, Indications

  • Used almost exclusively for opiate reversal
  • Has been investigated for treating other conditions (eg, sepsis, hypovolemic or cardiogenic shock)
  • Used to test whether an endogenous opiate blockade will result in diminished tail chasing or other self-mutilating behaviors


Contraindications, Precautions, Warnings

  • Contraindications

Contraindicated in patients with hypersensitivity; should be used cautiously in patients with cardiac abnormalities and/or opioid dependency

  • Precautions

Poor reversal agent for buprenorphine

  • Warnings

When used to reduce postoperative dysphoria associated with perioperative opioids, dosage and administration rate must be carefully titrated or hyperalgesia may occur

Side Effects

  • Relatively free of side effects at usual doses
  • When used to reverse the effect of opioids, opioid analgesic activity can also be reversed 
  • Duration of action may be shorter than that of the narcotic being reversed; animals with signs of respiratory depression should be closely monitored because ventilatory support or additional doses of naloxone may be required

Drug Interactions

  • May antagonize the effects of opioid partial agonists (eg, buprenorphine, butorphanol, pentazocine, nalbuphine) 
  • May reduce hypotensive and bradycardic effects of clonidine; potentially useful for clonidine overdoses
  • May increase the CNS effects of yohimbine
  • May increase plasma cortisol levels


  • Respiratory rate and depth
  • CNS function
  • Pain associated with opiate reversal

Client Information

  • Use only with direct professional supervision 

Dosage Forms

  • No veterinary-labeled products are currently available
  • Naloxone HCl injection 0.4 mg/mL and 1 mg/mL 

Compiled and summarized from Plumb’s Veterinary Drugs by Shannon Palermo, VMD

Information about this drug was adapted from Plumb’s Veterinary Drugs. Further details and more therapeutics can be found with a subscription at

Material from Veterinary Team Brief may not be reproduced, distributed, or used in whole or in part without prior permission of Educational Concepts, LLC. For questions or inquiries please contact us.

Practice Tools



Veterinary Team Brief delivers practical skills for team-based medicine—with clinical strategies for team training, peer-reviewed credibility, concise content, essential training modules, and easy-to-implement protocols. From the publisher of Clinician's Brief.

© 2018 Educational Concepts, L.L.C. dba Brief Media ™ All Rights Reserved. Privacy Policy (Updated 05/08/2018) Terms of Use (Updated 02/09/2015)