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Codeine

Opioid Analgesic / Antitussive
Last reviewed 21 Apr 2026 · PetCare.AI Editorial Team
Species
Dog, Cat
Brands
2 available
Interactions
2 documented
Formulations
2

Mechanism of action

Prodrug converted to morphine by CYP2D6 hepatic metabolism. Acts on mu-opioid receptors to provide analgesia and antitussive effects. Approximately 10% as potent as morphine.

At a glance

Class
Opioid Analgesic / Antitussive
Schedule
Controlled Substance
Storage
Store at room temperature, protect from light; controlled substance storage required

Dosing

🐕

Dog

Used for cough suppression and mild-to-moderate pain
Dose
1–2 mg/kg
Route
PO
Frequency
q6–8h
🐈

Cat

Cats have limited glucuronidation capacity — use with great caution
Dose
0.1–1 mg/kg
Route
PO
Frequency
q4–6h

Formulations

💊

Other — 2

Strength
—
Strength
—

Storage

Store at room temperature, protect from light; controlled substance storage required

Safety

Monitoring parameters

Respiratory rateSedation levelGI motilityPain assessment

Interactions

Major — 2

Fluoxetine
major
Codeine requires CYP2D6 conversion to active morphine. Fluoxetine potently inhibits CYP2D6, blocking codeine activation and rendering it ineffective as analgesic/antitussive.
Management: Codeine will be ineffective. Use alternative opioid not requiring CYP2D6 activation (hydromorphone, morphine, fentanyl).
Paroxetine
major
Paroxetine is the most potent CYP2D6 inhibitor among SSRIs. Completely blocks codeine conversion to morphine.
Management: Codeine will be ineffective. Use direct-acting opioid instead.

Brands

Other markets

Tylenol with Codeine (combination)
Codeine Phosphate

FAQs

Frequently asked questions

›What is Codeine?
Codeine is a opioid analgesic / antitussive used in pets. Prodrug converted to morphine by CYP2D6 hepatic metabolism. Acts on mu-opioid receptors to provide analgesia and antitussive effects. Approximately 10% as potent as morphine.
›What is Codeine used for in pets?
Codeine is used in veterinary medicine for: Used for cough suppression and mild-to-moderate pain; Cats have limited glucuronidation capacity — use with great caution.
›What is the Codeine dose for dogs?
For dogs, Codeine is typically dosed as follows — Used for cough suppression and mild-to-moderate pain: 1–2 mg/kg PO q6–8h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›What is the Codeine dose for cats?
For cats, Codeine is typically dosed as follows — Cats have limited glucuronidation capacity — use with great caution: 0.1–1 mg/kg PO q4–6h. Always consult your veterinarian for a dose tailored to your pet's weight, age, and condition.
›Does Codeine need a prescription?
Codeine is available over the counter. Even so, you should consult your veterinarian before giving any medication to your pet.

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 →