Hydrocodone
Hydrocodone bitartrate
Also known as: Tussigon · Hycodan · Vicodin · Lortab · Norco · Hydromet · Hydromide · Hydropane · Biocodone · Dicodid · Hydrokon · Robidone · hydrocodone tartrate · dihydrocodeinone acid tartrate · hydrocodone acid tartrate · hydrocodoni bitartras · hydrocone bitartrate
Reviewed by the VetSheet Veterinary TeamUpdated Apr 5, 2026Evidence-based veterinary reference
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Dosing by species
🌎 NA — North America🌍 EU — Europe
Dogs
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| For cough | 0.22 mg/kg PO q6-12h | PO | q6-12h | — | 🌎 NA |
| As an analgesic using fixed dose combination products with acetaminophen | 0.22-0.5 mg/kg of the hydrocodone component PO q8-12h | PO | q8-12h | — | 🌎 NA |
| For cough using Hycodan (or equivalent) | ¼ to 1 tablet (5 mg) once to 4 times daily | PO | q6-24h | — | 🌎 NA |
| For lick granulomas | 5-10 mg (1-2 tablets) per 20 kg of body weight PO three times daily | PO | TID | — | 🌎 NA |
| For adjunctive treatment of opioid-related stereotypies, lick granuloma | 0.22-0.25 mg/kg PO q8-12h | PO | q8-12h | — | 🌎 NA |
- For cough: Goal is to suppress coughing without causing excessive sedation
- As an analgesic using fixed dose combination products with acetaminophen: Do not exceed 15 mg/kg of the acetaminophen component q8h.
- For cough using Hycodan (or equivalent): In small and medium sized dogs.
- For adjunctive treatment of opioid-related stereotypies, lick granuloma: Supplies exogenous opioids to decrease the need for self-stimulation.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| For adjunctive treatment of opioid-related stereotypies | 1.25-5 mg per cat PO q12h | PO | q12h | — | 🌎 NA |
- For adjunctive treatment of opioid-related stereotypies: Do NOT use any product that contains acetaminophen.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Hydrocodone is a phenanthrene-derivative opiate agonist used primarily in veterinary medicine as a potent antitussive (cough suppressant) for dogs.
- Primary Indications: Management of harsh, dry, non-productive coughs associated with conditions like collapsing trachea, bronchitis, or canine infectious tracheobronchitis (kennel cough).
- Behavioral Use: Occasionally used to treat opioid-related behavioral problems (e.g., lick granulomas, stereotypies) by providing an exogenous opioid source to reduce self-stimulating behaviors.
- Analgesia: Combination products containing acetaminophen can be used for moderate oral analgesia in dogs.
CRITICAL WARNING: Combination products containing acetaminophen (e.g., Vicodin®, Lortab®) are STRICTLY CONTRAINDICATED IN CATS due to fatal acetaminophen toxicity.
Mechanism of action
Hydrocodone acts primarily by binding to mu-opioid receptors in the central nervous system.
- Antitussive Effect: Direct suppression of the cough reflex at the cough center in the medulla oblongata.
- Analgesic Effect: Binds to pre- and post-synaptic mu-receptors in the brain and spinal cord → inhibits release of nociceptive neurotransmitters (like Substance P) → hyperpolarizes neurons → decreases excitability and pain transmission.
- Respiratory Effects: Tends to have a drying effect on respiratory mucosa, increasing the viscosity of secretions. The addition of homatropine methylbromide (an anticholinergic) in some formulations enhances this drying effect.
Safety & warnings
Contraindications
- Hypersensitivity to narcotic analgesics
- Patients receiving monoamine oxidase inhibitors (MAOIs, e.g., selegiline)
- Diarrhea caused by toxic ingestion (until toxin is eliminated)
- Acetaminophen-containing products MUST NOT be used in cats
Adverse effects
- Sedation
- Constipation (especially with chronic therapy)
- Vomiting
- Gastrointestinal disturbances
- Masking of clinical signs of underlying respiratory disease
Precautions
Use with caution in patients with hypothyroidism, severe renal insufficiency, adrenocortical insufficiency (Addison's disease), head injuries, increased intracranial pressure, acute abdominal conditions, and in geriatric or severely debilitated patients.
Use with extreme caution in patients suffering from respiratory diseases when respiratory secretions are increased or when liquids are nebulized into the respiratory tract.
Note: Hydrocodone products have a relatively high abuse potential in humans. Veterinarians should be vigilant for drug-seeking behavior from clients.
Drug interactions
May cause additive hypotension in dogs with collapsing trachea
May cause additive anticholinergic effects
May potentiate the adverse effects associated with the antidepressant
May cause increased CNS or respiratory depression
Monitoring
- Clinical efficacy (reduction in cough frequency/severity, pain relief)
- Adverse effects (excessive sedation, constipation, respiratory depression)
Pharmacokinetics
Half-life
Absorption
Oral bioavailability of 40%-80% in dogs. Well absorbed after oral administration in humans.
Distribution
Unknown if hydrocodone enters milk.
Metabolism
Partially metabolized to hydromorphone in the liver.
Elimination
Excreted primarily via the kidneys.
Overdose
Massive overdose primarily causes CNS, cardiovascular, and respiratory depression secondary to opiate effects.
- Treatment: If ingestion was recent, empty the gut using standard protocols. Administer naloxone to reverse opioid effects as necessary.
- Note on Homatropine: The homatropine ingredient in some formulations may cause anticholinergic effects, but its relatively low toxicity usually does not require specific treatment.
Available products
Formulations
- Oral Tablets
- Oral Syrup
- Combination products (with homatropine, acetaminophen, decongestants, or antihistamines)
Human-labeled
- Hydrocodone Bitartrate Oral Tablets: 5 mg with Homatropine MBr 1.5 mg (Tussigon®, Hycodan®)
- Hydrocodone Bitartrate Oral Syrup: 5 mg with Homatropine MBr 1.5 mg per 5 mL (Hycodan®, Hydromet®, Hydromide®, Hydropane®)
- Hydrocodone/Acetaminophen Oral Tablets: 5 mg/325mg, 5 mg/500 mg, 7.5 mg/325mg, 10 mg/325mg (Vicodin®, Norco®, Lortab®)
- Hydrocodone/Acetaminophen Oral Elixir: 2.5 mg hydrocodone and 167 mg acetaminophen per 5 mL
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Products should be protected from light and stored at room temperature.
Client information
Administer exactly as prescribed by your veterinarian.
- Do not give human pain medications (like Vicodin or Lortab) to your pets without explicit veterinary instructions. These products contain acetaminophen, which is highly toxic and often fatal to cats.
- This medication may cause your pet to become sleepy or sedated.
- Constipation can occur with long-term use; monitor your pet's bowel movements.
- Because this is a controlled substance with potential for human abuse, store it securely out of reach of children and other pets.
VetSheet drug reference is intended for licensed veterinary professionals as a clinical decision-support aid, not a substitute for professional judgement or the manufacturer’s current label.