Pet Safety / Compounds / Codeine

Is Codeine safe for dogs and cats?

Very high risk for cats · High risk for dogs

Not veterinary or professional safety advice, and not a substitute for a veterinarian — consult one about your animal. Full disclaimer →

Cats lack efficient glucuronidation; opioid effects prolonged and intensified. Even small doses can be fatal.

What is codeine?

The IUPAC name is (4R,4aR,7S,7aR,12bS)-9-methoxy-3-methyl-2,4,4a,7,7a,13-hexahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinolin-7-ol.

Also known as: MFCD00270393, STL581484, Methylmorphine, Codicept.

IUPAC name
(4R,4aR,7S,7aR,12bS)-9-methoxy-3-methyl-2,4,4a,7,7a,13-hexahydro-1H-4,12-methanobenzofuro[3,2-e]isoquinolin-7-ol
CAS number
76-57-3
Molecular formula
C18H21NO3
Molecular weight
299.4 g/mol
SMILES
CN1CC[C@]23[C@@H]4[C@H]1CC5=C2C(=C(C=C5)OC)O[C@H]3[C@H](C=C4)O
PubChem CID
5284371

Risk for dogs

High risk

Dogs metabolize codeine to morphine; sensitive to opioid respiratory depression. Accidental ingestion of human medication is common.

Risk for cats

Very high risk

Cats lack efficient glucuronidation; opioid effects prolonged and intensified. Even small doses can be fatal.

Regulatory consensus

2 regulatory and scientific bodies have classified Codeine. The classifications differ — that's the data.

AgencyYearClassificationNotes
DEA1970Schedule II controlled substance (pure) / Schedule III-V in combinations
WHO2023Essential Medicine — Step 2 analgesic ladder

Regulators apply different standards of evidence — animal-data weighting, exposure-pattern assumptions, epidemiological power thresholds — which is why two scientific bodies can review the same data and reach different conclusions. The disagreement is the data.

Where pets encounter codeine

  • Pharmaceutical
  • Illicit Drug

Safer alternatives

Lower-risk approaches that achieve a similar outcome to Codeine:

  • Ibuprofen + acetaminophen combination
    Trade-offs: No cough suppressant effect. GI side effects (ibuprofen). Hepatotoxicity risk (acetaminophen overdose). Non-addictive.
    Relative cost: Lower
  • Dextromethorphan (DXM)
    Trade-offs: Non-opioid cough suppressant. Abuse potential at high doses. Less effective for severe cough.
    Relative cost: Similar

Frequently asked questions

Is codeine safe for pets?

Cats lack efficient glucuronidation; opioid effects prolonged and intensified. Even small doses can be fatal.

Why do regulators disagree about codeine?

Codeine has been classified by 2 agencies including DEA, WHO, with differing conclusions. Regulators apply different standards of evidence (animal data weighting, exposure-pattern assumptions, epidemiological power thresholds), which is why two scientific bodies can review the same data and reach different conclusions. See the regulatory consensus table on this page for the full picture.

See Codeine in the pets app

Look up products containing codeine, compare to alternatives, and explore the full data record.

Open in pets View raw API data

Sources (5)
  1. —
  2. DEA Codeine scheduling (Schedule II / III / V depending on formulation) (2023) — regulatory
  3. WHO Essential Medicines List — Codeine analgesic and antitussive (2023) — regulatory
  4. FDA codeine label — pediatric contraindication for tonsillectomy/adenoidectomy (2017) — regulatory
  5. ASPCA APCC opioid pet-toxicity reporting (2023) — industry

Reference data, not professional advice. Aggregates publicly available regulatory and scientific data; not a substitute for veterinary, medical, legal, or regulatory advice. Why we built ALETHEIA →