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Naloxone

Prescription
Opioid antagonist (pure mu, kappa, delta antagonist)
Last reviewed 19 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
3 available
Interactions
2 documented
Formulations
2

Mechanism of action

Competitively binds all opioid receptor subtypes (mu, kappa, delta) with highest affinity for mu receptors, rapidly displacing opioid agonists and reversing their effects

At a glance

Class
Opioid antagonist (pure mu, kappa, delta antagonist)
Schedule
Prescription
Storage
Store below 25°C, protect from light

Dosing

🐕

Dog

Opioid reversal (respiratory depression, overdose)
Dose
0.01–0.04 mg/kg
Route
IV, IM, SC, Intranasal
Frequency
q2–3 min until effect; may need repeat doses
Max dose
2 mg/dose; 10 mg/day
Duration: Short-acting (30–90 min); re-narcotization possible
🐈

Cat

Opioid reversal
Dose
0.01–0.04 mg/kg
Route
IV, IM, SC
Frequency
q2–3 min until effect
Max dose
0.4 mg/dose; 2 mg/day
Duration: Short-acting; monitor for renarcotization

Formulations

💉

Injection — 2

Strength
0.4mg/mL
Available in India
Strength
1mg/mL

Storage

Store below 25°C, protect from light

Safety

Absolute contraindications — do not use

  • Known hypersensitivity to naloxone

Use with caution

  • Opioid-dependent patients
    May precipitate acute withdrawal and severe pain
  • Cardiac disease
    Rapid reversal may cause catecholamine surge

Adverse effects

Common
Return of pain
Tachycardia
Excitement/dysphoria
Serious
Acute opioid withdrawal
Pulmonary edema (rare)
Cardiac arrhythmias
Seizures (rare)

Monitoring parameters

Respiratory rateHeart ratePain assessmentLevel of consciousnessMonitor for renarcotization (naloxone shorter acting than many opioids)

Interactions

Minor — 2

Fentanyl
minor
Naloxone is a mu-opioid antagonist — reverses fentanyl effects (intentional use for overdose reversal)
Management: This is the intended use. Give naloxone IV to reverse fentanyl respiratory depression. Effect is shorter than fentanyl — may need repeat doses.
Butorphanol
minor
Naloxone reverses butorphanol's opioid effects (intended reversal agent)
Management: Standard reversal. Naloxone will reverse both sedation and analgesia.

Brands

International

Narcan
Adapt Pharma

India

Nalox
Samarth
Nalone
Neon Labs

FAQs

Frequently asked questions

›What is Naloxone?
Naloxone is a opioid antagonist (pure mu, kappa, delta antagonist) used in pets. Competitively binds all opioid receptor subtypes (mu, kappa, delta) with highest affinity for mu receptors, rapidly displacing opioid agonists and reversing their effects
›What is Naloxone used for in pets?
Naloxone is used in veterinary medicine for: Opioid reversal (respiratory depression, overdose); Opioid reversal.
›What is the Naloxone dose for dogs?
For dogs, Naloxone is typically dosed as follows — Opioid reversal (respiratory depression, overdose): 0.01–0.04 mg/kg IV/IM/SC/Intranasal q2–3 min until effect; may need repeat doses. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What is the Naloxone dose for cats?
For cats, Naloxone is typically dosed as follows — Opioid reversal: 0.01–0.04 mg/kg IV/IM/SC q2–3 min until effect. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What are the side effects of Naloxone?
Common: Return of pain, Tachycardia, Excitement/dysphoria. Serious (call your vet immediately): Acute opioid withdrawal, Pulmonary edema (rare), Cardiac arrhythmias, Seizures (rare).
›Does Naloxone need a prescription?
Yes. Naloxone is a prescription medication and should only be administered under veterinary supervision.
›When should Naloxone not be used?
Do not use Naloxone if: Known hypersensitivity to naloxone.

References

References

Textbooks & handbooks

  • Plumb, D.C. Plumb's Veterinary Drug Handbook. 10th ed., Wiley-Blackwell, 2023.
  • Vail, D.M., Thamm, D.H., & Liptak, J.M. (eds.). Withrow & MacEwen's Small Animal Clinical Oncology. 6th ed., Saunders/Elsevier, 2020.
  • Riviere, J.E., & Papich, M.G. (eds.). Veterinary Pharmacology and Therapeutics. 10th ed., Wiley-Blackwell, 2018.
  • National Research Council. Nutrient Requirements of Dogs and Cats. National Academies Press, Washington DC, 2006.
  • The Merck Veterinary Manual. Merck & Co., Online edition. https://www.merckvetmanual.com/

Clinical guidelines & consensus

  • Fletcher, D.J., Boller, M., Brainard, B.M., et al. "RECOVER Evidence and Knowledge Gap Analysis on Veterinary CPR." Journal of Veterinary Emergency and Critical Care, 2012;22(S1):S102–S131.
  • American Animal Hospital Association. 2018 AAHA Diabetes Management Guidelines for Dogs and Cats. AAHA Press.

Journals & peer-reviewed studies

  • Hogan, D.F., Fox, P.R., Jacob, K., et al. "Secondary prevention of cardiogenic arterial thromboembolism in the cat: The FAT CAT study." Journal of Veterinary Cardiology, 2015;17(Suppl 1):S306–S317.
  • Boswood, A., Häggström, J., Gordon, S.G., et al. "Effect of Pimobendan in Dogs with Preclinical Myxomatous Mitral Valve Disease and Cardiomegaly: The EPIC Study — A Randomized Clinical Trial." Journal of Veterinary Internal Medicine, 2016;30(6):1765–1779.
  • ASPCA Animal Poison Control Center. Toxicology and Poison Management Guidelines. American Society for the Prevention of Cruelty to Animals. https://www.aspca.org/pet-care/animal-poison-control

Regulatory & approvals

  • Central Drugs Standard Control Organisation (CDSCO), Government of India. Veterinary Drug Approval Registry, 1969–2026. Directorate General of Health Services. https://cdsco.gov.in/

Databases

  • Washington State University, College of Veterinary Medicine. Veterinary Clinical Pharmacology Laboratory (VCPL) — MDR1 Multidrug Sensitivity Database. https://vcpl.vetmed.wsu.edu/
Educational reference only
This information is provided for educational purposes and is not a substitute for professional veterinary advice, diagnosis, or treatment. Always consult a qualified veterinarian before administering any medication to your pet. Find a vet near you →

Related medicines

Other medicines in the same class (Opioid antagonist).

Naltrexone
Rx
Long-acting competitive antagonist at mu, kappa, and delta opioid receptors. Unlike naloxone, naltrexone has high oral bioavailability and long half-life (10–13h). Used for opioid dependence, compulsive behaviors, and pruritus.
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