Codeine
Codeine is used empirically for cough or mild pain, but canine oral analgesic reliability is limited.
Group
Opioid analgesic and antitussive
Mechanism of Action
Produces opioid receptor effects, partly dependent on metabolism to active compounds.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Analgesia | 0.5–1 mg/kg | PO | Every 4–6 h | |
| Cough suppression | 0.1–0.3 mg/kg | PO | Every 4–6 h | |
| Cough suppression | 1–2 mg/kg | PO | Every 6–12 h | |
| Cough suppression | 0.1–0.3 mg/kg | PO | Every 8–12 h | |
| Analgesia | 0.5–2 mg/kg | PO | Every 6–12 h | Titrate to effect; do not give acetaminophen-containing combinations to cats. |
| Antidiarrheal use | 0.25–0.5 mg/kg | PO | Every 6–8 h | Do not suppress diarrhea from toxin ingestion before toxin clearance; avoid repeated use with severe inflammatory bowel disease. |
| Higher-dose analgesic alternative | Reference only | PO | The older source gives codeine alone 1–4 mg/kg orally every 1–6 hours, an unusually broad schedule. Preserve for specialist review rather than recommending the shortest interval automatically. | |
| Codeine-acetaminophen analgesia | Reference only | PO | A tablet with 60 mg codeine and 300 mg acetaminophen is described at 1–2 mg/kg CODEINE every 6–8 hours. Do not treat it as combined-total dosing; the codeine salt basis and independently safe acetaminophen exposure must both be established. Never give this combination to cats. |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Analgesia | 0.5 mg/kg | PO | Every 6 h | Titrate to response; avoid acetaminophen-containing products. |
| Cough suppression | 0.1 mg/kg | PO | Every 6 h | |
| Analgesia | 0.5–2 mg/kg | PO | Every 6–12 h | Titrate to effect; do not give acetaminophen-containing combinations to cats. |
| Analgesia | 0.5–2 mg/kg | PO | Every 6–8 h |
Rabbits
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Historical combination elixir in water | Reference only | PO | One mL acetaminophen/codeine elixir in 10–20 mL drinking water is described without ingredient strengths or intake; no dose or preparation is inferred. |
Indications
- Cough suppression
- Mild pain
Contraindications
- Do not give cats codeine combinations containing acetaminophen.
- Avoid unassessed multi-ingredient cough preparations.
- MAO-inhibitor treatment or opioid hypersensitivity.
- Diarrhea from uneliminated toxicants or repeated treatment of severe inflammatory bowel disease.
- Severe respiratory compromise or increased intracranial pressure requires extreme caution.
Interactions
- Other sedatives and CNS depressants increase depression.
- Anticholinergics increase constipation risk; antidepressants and other sedatives increase CNS/respiratory depression.
- Quinidine can inhibit conversion to morphine, potentially changing analgesic response.
Adverse effects
- Sedation
- Excitement, especially in cats
- Constipation
- Dependence with prolonged treatment
Toxicity
Support respiration in severe depression; naloxone reverses serious opioid effects.
Monitoring and Administration
Monitor breathing, heart rate and clinical response. Analgesic response varies and tolerance may require reassessment.
Codeine phosphate and sulfate are different salt formulations. Generic listed strengths do not establish their free-base equivalence, so no unverified salt conversion is used.
The cited canine acetaminophen–codeine example favors the lower 30 mg codeine tablet over 60 mg because of sedation, but this is not a general combination dosing rule.
Listed presentations are 15, 30 and 60 mg tablets and 5 mg/mL syrup or 3 mg/mL solution; their exact salt basis and complete ingredients are not specified, so product conversions are not encoded.