Carbamazepine
5H-Dibenz[b,f]azepine-5-carboxamide
Also known as: Tegretol · Carbatrol · Epitol · Equetro · G-32883 · carbamazepinum · karbamatsepiini · karbamazepinas
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 |
|---|---|---|---|---|---|
| As a psychotherapeutic agent | 4-8 mg/kg PO q12h | PO | q12h | — | 🌎 NA |
- As a psychotherapeutic agent: Not commonly used, but may have some utility in dogs that seem to have amygdalar hyperactivity; sometimes used in conjunction with SSRIs to control explosive aggression.
Horses
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| For photic head shaking | 10 mg/kg PO q6h or 29 mg/kg PO q12h | PO | q6h or q12h | — | 🌎 NA |
- For photic head shaking: May be helpful in some horses that do not respond to cyproheptadine.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Carbamazepine is a dibenzoazepine iminostilbene derivative that is chemically related to the tricyclic antidepressant imipramine.
Clinical Pearl: While widely used in human medicine as a primary anticonvulsant and mood stabilizer, its utility in veterinary medicine (particularly in dogs) is severely limited by its rapid hepatic autoinduction. Dogs metabolize the drug so quickly after a few days of therapy that maintaining therapeutic serum levels becomes exceedingly difficult.
Because of this pharmacokinetic limitation, it is rarely used for seizure control in animals. Instead, in veterinary medicine, it is primarily reserved for:
- Behavioral medicine in dogs (e.g., managing amygdalar hyperactivity or explosive aggression, often alongside SSRIs).
- Neuropathic pain or specific neurologic conditions like photic head shaking in horses that are refractory to other treatments like cyproheptadine.
Mechanism of action
Carbamazepine primarily acts by blocking voltage-gated sodium channels in neuronal membranes.
- Mechanism: Binds preferentially to the inactive state of sodium channels → delays their recovery → inhibits repetitive neuronal firing and stabilizes hyperexcited neural membranes.
- It also decreases the synaptic transmission of excitatory impulses and may reduce the release of the excitatory neurotransmitter glutamate.
- Structurally related to tricyclic antidepressants, it also possesses mild anticholinergic, antidiuretic, and muscle relaxant properties.
Safety & warnings
Contraindications
- Patients receiving MAO Inhibitors (e.g., selegiline) within the past 14 days
- Patients with a history of bone marrow depression
- Known hypersensitivity to carbamazepine or tricyclic antidepressants
Adverse effects
- Sedation and lethargy
- Ataxia (unsteadiness)
- Gastrointestinal upset (vomiting, anorexia)
- Hepatotoxicity (elevated liver enzymes)
- Blood dyscrasias (rare but possible bone marrow suppression)
Precautions
Use with extreme caution due to extensive drug interactions (it is a potent inducer of hepatic enzymes). In dogs, it rapidly induces its own metabolism (autoinduction), making long-term therapeutic dosing difficult. May interfere with thyroid function tests (decreased values) and some pregnancy tests, though veterinary significance is unclear.
Drug interactions
May increase plasma levels or effects of carbamazepine
May increase plasma levels or effects of carbamazepine; Carbamazepine may also decrease their effects
May increase plasma levels or effects of carbamazepine
May increase plasma levels or effects of carbamazepine
May increase plasma levels or effects of carbamazepine
May increase plasma levels or effects of carbamazepine; Carbamazepine may also increase effects of Isoniazid
May increase plasma levels or effects of carbamazepine
Contraindicated; discontinue MAOI at least 14 days prior to carbamazepine
May increase plasma levels or effects of carbamazepine
May increase plasma levels or effects of carbamazepine
May increase plasma levels or effects of carbamazepine; Carbamazepine may also decrease their effects, though it can increase Clomipramine levels
May increase plasma levels or effects of carbamazepine; Carbamazepine may decrease its effects and increase risk for phenobarbital toxicity
May decrease plasma levels or effects of carbamazepine
May decrease plasma levels or effects of carbamazepine
May decrease plasma levels or effects of carbamazepine
May decrease plasma levels or effects of carbamazepine
May decrease plasma levels or effects of carbamazepine
May decrease plasma levels or effects of carbamazepine
May decrease plasma levels or effects of carbamazepine
May decrease plasma levels or effects of carbamazepine
Carbamazepine may decrease its effect by lowering serum concentrations
Carbamazepine may decrease its effect by lowering serum concentrations
Carbamazepine may decrease its effect by lowering serum concentrations
Carbamazepine may decrease its effect by lowering serum concentrations
Carbamazepine may decrease its effect by lowering serum concentrations
Carbamazepine may decrease its effect by lowering serum concentrations
Carbamazepine may decrease its effect by lowering serum concentrations
Carbamazepine may decrease its effect by lowering serum concentrations
Carbamazepine may decrease its effect by lowering serum concentrations
Carbamazepine may decrease its effect by lowering serum concentrations
Carbamazepine may decrease its effect by lowering serum concentrations
Carbamazepine may decrease its effect by lowering serum concentrations
Carbamazepine may decrease its effect by lowering serum concentrations
Carbamazepine may decrease its effect by lowering serum concentrations
Carbamazepine may decrease its effect by lowering serum concentrations
Carbamazepine may decrease its effect by lowering serum concentrations
Carbamazepine may decrease its effect by lowering serum concentrations
Carbamazepine may decrease its effect by lowering serum concentrations
Monitoring
- Complete Blood Count (CBC)
- Liver function tests
- Clinical efficacy and behavioral changes
Pharmacokinetics
Half-life
Absorption
Variable and relatively slow oral absorption.
Distribution
Widely distributed into tissues; highly protein-bound.
Metabolism
Extensively metabolized in the liver. In dogs, it is a potent inducer of hepatic microsomal enzymes and rapidly induces its own metabolism (autoinduction) within days of starting therapy.
Elimination
Excreted primarily in the urine as metabolites.
Overdose
Overdose can lead to significant CNS depression, severe ataxia, tremors, seizures, respiratory depression, and cardiovascular abnormalities (tachycardia, hypotension). Treatment is primarily supportive and symptomatic, including gastric decontamination if caught early, IV fluids, and respiratory support. Seizures should be treated with standard anticonvulsants (e.g., diazepam, phenobarbital).
Available products
Formulations
- Oral Tablets
- Oral Chewable Tablets
- Extended-Release Tablets/Capsules
- Oral Suspension
Human-labeled
- Carbamazepine Oral Tablets: 100 mg (regular and chewable), & 200 mg (Tegretol, Epitol, generic)
- Carbamazepine Oral Tablets or Capsules Extended-Release (12-hour) (Tegretol XR, Carbatrol, Equetro, generic)
- Carbamazepine Oral Suspension (Tegretol, generic)
Regulatory status
No regulatory data for: 🇺🇸 US · 🇪🇺 EU · 🇬🇧 UK · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Store below 30°C (86°F) in airtight containers, as humid conditions can reduce potency by up to one-third. Protect from light. Compounded oral suspension (40 mg/mL in simple syrup) retains >90% potency for 90 days stored at both 5°C and 25°C, but must be protected from light and shaken vigorously before use.
Client information
Your veterinarian has prescribed carbamazepine for your pet. Please read the following carefully:
- Off-Label Use: This medication is used "off-label" in veterinary medicine. It is used infrequently, and your veterinarian has prescribed it based on your pet's specific behavioral or neurological needs.
- Strict Schedule: It is crucial to give this medication exactly as prescribed. Because animals process this drug very quickly, missing a dose can lead to a loss of effectiveness. It often requires frequent administration.
- What to Watch For: Monitor your pet for signs of lethargy, unsteadiness (ataxia), or gastrointestinal upset (vomiting, loss of appetite).
Important: Report any unusual behavior, severe vomiting, or yellowing of the eyes/gums (jaundice) to your veterinarian immediately, as these could be signs of liver stress or adverse reactions.
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.