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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

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

Frequency

q6–8h

🐈

Cat

Cats have limited glucuronidation capacity — use with great caution

Dose

0.1–1 mg/kg

Route

Frequency

q4–6h

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 →

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

Educational reference only

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.

Educational reference only

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.

Educational reference only

References

The PetCare.AI drug reference is built from 13 authoritative sources cited across 580 drug monographs.

Textbooks & handbooks — 5

Plumb's Veterinary Drug Handbook
Withrow & MacEwen's Small Animal Clinical Oncology
Merck Veterinary Manual
NRC Nutrient Requirements of Dogs and Cats
Veterinary Pharmacology and Therapeutics (Riviere & Papich)

Clinical guidelines & consensus — 4

ASPCA Animal Poison Control Center Guidelines
AAHA Diabetes Management Guidelines
ASPCA Poison Control Guidelines
RECOVER CPR Guidelines

Journals & peer-reviewed studies — 2

EPIC Study (J Vet Intern Med 2016)
JVIM FAT CAT Study

Regulatory & approvals — 1

CDSCO Veterinary Drug Approval Registry (1969–2026)

Databases — 1

Washington State University VCPL MDR1 Database