Naloxone

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

Monitoring

• 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 plumbsveterinarydrugs.com.