Clonazepam
Clonazepam is a benzodiazepine with anticonvulsant, anxiolytic and muscle-relaxant activity. Veterinary use is extra-label and largely empirical, including selected seizure and behavioral indications. Its relatively prolonged action can be useful in some treatment plans, while development of tolerance influences its role in sustained seizure management.
Group
Benzodiazepine
Mechanism of Action
Clonazepam acts as a positive allosteric modulator at benzodiazepine-sensitive GABA-A receptors. In the presence of GABA, it increases the frequency of chloride-channel opening, strengthening inhibitory neurotransmission. The resulting reduction in neuronal excitability produces anticonvulsant, anxiolytic and muscle-relaxant effects. It enhances the action of endogenous GABA rather than directly replacing that neurotransmitter.
Dose Rates
Dogs
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Seizures or anxiety | 0.5 mg/kg | PO | Every 8–12 h | |
| Lower-dose treatment in sensitive dogs | 0.1–0.2 mg/kg | PO | Dose reduction described for sensitive dogs; the passage does not separately assign a repeat interval. | |
| Adjunctive seizure treatment | 1–2 mg/kg | PO | Every 12 h | Historical higher-dose anticonvulsant alternative, distinct from lower anxiolytic dosing. |
| Adjunctive seizure treatment | 0.5 mg/kg | PO | Every 8–12 h | Concurrent phenobarbital may need a 10–20% reduction if sedation or interaction warrants it. |
| Anxiety | 0.05–0.25 mg/kg | PO | Every 12–24 h | |
| Anxiety | 0.1–1 mg/kg | PO | Every 8–12 h |
Cats
| Use / stage | Dose | Route | Schedule | Instructions |
|---|---|---|---|---|
| Seizures or anxiety | 0.1–0.2 mg/kg | PO | Every 12–24 h | |
| Anxiety | 0.05–0.25 mg/kg | PO | Every 12–24 h | |
| Anxiety | 0.02–0.2 mg/kg | PO | Every 12–24 h | |
| Anxiety | 0.1–0.2 mg/kg | PO | As needed | Historical alternative used up to twice daily; avoid repeated dosing without reassessing sedation. |
| Adjunctive seizure treatment — Initial | 0.5 mg/animal | PO | Every 12–24 h | |
| Adjunctive seizure treatment | 0.0625–0.125 mg/animal | PO | Every 8–12 h | Equivalent to one-eighth to one-quarter of a 0.5 mg tablet. Small physical fractions may be inaccurate; monitor hepatic function. |
Indications
- Adjunctive treatment of selected seizure disorders in dogs and cats, with long-term usefulness influenced by tolerance.
- Empirical short-term or adjunctive treatment of selected anxiety, panic or fear-related behavioral disorders in dogs and cats.
Contraindications
- Use cautiously during pregnancy; veterinary reproductive risk is not defined.
- Significant hepatic dysfunction, acute narrow-angle glaucoma or benzodiazepine hypersensitivity.
- Use cautiously with myasthenia gravis.
Interactions
- Other sedatives and CNS depressants increase depression.
- Cimetidine can reduce benzodiazepine metabolism; concurrent phenobarbital may alter response.
- Azole antifungals and erythromycin can increase exposure; phenytoin, phenobarbital and rifampin can reduce concentrations.
Adverse effects
- Sedation
- Polyphagia
- Paradoxical excitement
- Possible severe hepatic injury in cats
Preparations
| Preparation | Form | Strength | Route |
|---|---|---|---|
| Clonazepam 0.5 mg tablet | Tablet | 0.5 mg / tablet | PO |
| Clonazepam 1 mg tablet | Tablet | 1 mg / tablet | PO |
| Clonazepam 2 mg tablet | Tablet | 2 mg / tablet | PO |
| Clonazepam 0.125 mg orally disintegrating tablet | Tablet | 0.125 mg / tablet | PO |
| Clonazepam 0.25 mg orally disintegrating tablet | Tablet | 0.25 mg / tablet | PO |
| Compounded clonazepam oral suspension 0.1 mg/mL Specific Ora-Plus/Ora-Sweet or SF formulation; 60-day reported potency at 5°C or 25°C protected from light. | Oral Liquid | 0.1 mg / mL | PO |
Monitoring and Administration
Assess sedation and response. Sensitive dogs may require the lower 0.1–0.2 mg/kg range rather than the standard listed dose.
Compounded oral products have described stability for 60 days. Avoid adsorption losses in soft PVC containers.
Monitor hepatic function in cats. A reported therapeutic blood concentration is 0.015–0.07 mcg/mL, but clinical response and assay specificity remain important.