Potassium bromide
Also known as: Bromilep · Epilease · Libromide · KBr
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 |
|---|---|---|---|---|---|
| Control of seizures (Maintenance) | 20-40 mg/kg | PO | q24h | Long-term | 🌍 EU |
| Control of seizures (5-day Loading Dose) | 200 mg/kg/day divided into 4-6 hour doses | PO | Divided q4-6h | 5 days | 🌍 EU |
| Control of seizures (Single Loading Dose) | 600-1000 mg/kg | PO | Single dose | Once | 🌍 EU |
| Control of seizures (Intrarectal Loading) | 100 mg/kg | PR | q4h | 6 doses (over 24 hours) | 🌍 EU |
- Control of seizures (Maintenance): Initial daily maintenance dose. More frequent dosing is not detrimental but not necessary.
- Control of seizures (5-day Loading Dose): After 5 days, decrease to maintenance dose (20-40 mg/kg p.o. q24h). If seizures resolve sooner, decrease to maintenance earlier to reduce adverse effects.
- Control of seizures (Single Loading Dose): Likely to result in excessive sedation, ataxia, and potentially vomiting.
- Control of seizures (Intrarectal Loading): Total 600 mg/kg over 24 hours. Use liquid bromide (250 mg/ml). Useful if animal is not conscious enough for oral medication.
Cats
| Indication | Dose | Route | Frequency | Duration | Region |
|---|---|---|---|---|---|
| Contraindicated | Do not use | PO | N/A | N/A | 🌍 EU |
- Contraindicated: Causes severe coughing due to eosinophilic bronchitis, which may be fatal.
Doses are a clinical reference for licensed veterinary professionals. Always confirm against the current label and the individual patient.
Overview
Potassium bromide (KBr) is an anticonvulsant medication primarily used as an adjunct or alternative therapy for the control of refractory seizures in dogs, particularly when phenobarbital alone is insufficient or contraindicated. It has a very long half-life, meaning steady-state therapeutic levels take months to achieve unless a loading dose is utilized.
CRITICAL WARNING: Potassium bromide is strictly contraindicated in cats due to the high risk of developing severe, potentially fatal eosinophilic bronchitis.
Clinical Pearl: Because bromide is measured by standard laboratory analyzers as chloride, patients on KBr will exhibit a pseudohyperchloremia (falsely elevated serum chloride levels).
Mechanism of action
Within the central nervous system, bromide competes with transmembrane chloride transport and inhibits sodium transport → resulting in membrane hyperpolarization and elevation of the seizure threshold.
Bromide also competes with chloride in post-synaptic anion channels following activation by inhibitory neurotransmitters → potentiates the effect of GABA. It acts synergistically with other GABA-ergic therapeutic agents (such as phenobarbital).
Safety & warnings
Contraindications
- Cats (causes severe, potentially fatal eosinophilic bronchitis)
- Dogs with a history of, or predisposition to, pancreatitis
Adverse effects
- Ataxia
- Sedation
- Somnolence
- Vomiting (especially with high concentration solutions >250 mg/ml)
- Polyphagia
- Polydipsia
- Pancreatitis
- Skin reactions (in animals with pre-existing skin diseases)
- Behavioural changes (irritability, restlessness)
- Transient diarrhoea (with intrarectal loading)
Precautions
Dietary Consistency: High levels of dietary salt increase renal elimination of bromide. It is critical that the patient's diet (including treats) be kept strictly constant once bromide therapy has started.
Laboratory Artifact: Bromide is measured in assays for chloride and will produce falsely high 'chloride' results.
Renal Impairment: Use with caution in dogs with renal disease, as bromide is eliminated by the kidneys.
Loading Dose Risks: Loading doses are associated with an increased incidence of adverse effects (sedation, ataxia) and should only be used in dogs with poorly controlled severe seizures.
Drug interactions
Increased dietary salt increases renal elimination of bromide, decreasing serum bromide concentrations.
Increases bromide excretion and lowers serum bromide levels.
Increases bromide excretion and decreases serum bromide concentrations.
Synergistic GABA-ergic anticonvulsant effects.
Monitoring
- Serum KBr concentrations (Therapeutic range: 0.8-1.5 mg/ml)
- Serum chloride (Note: KBr causes falsely elevated chloride readings on standard chemistry panels)
- Renal function (BUN, Creatinine, USG)
- Signs of excessive sedation, ataxia, or vomiting
- Pancreatic enzymes if clinical signs of pancreatitis develop
Pharmacokinetics
Half-life
Absorption
Well absorbed from the gastrointestinal tract.
Distribution
Slow rise of plasma bromide levels after enteral administration limits its usefulness in status epilepticus. Steady state plasma concentrations may not be achieved for 3-4 months.
Metabolism
Not metabolized by the liver.
Elimination
Eliminated slowly by the kidney in competition with chloride.
Overdose
Acute bromide toxicity (bromism) presents with profound sedation, ataxia, somnolence, and potentially vomiting.
Treatment of choice: Intravenous administration of 0.9% NaCl (normal saline). The chloride in the saline competes with bromide for renal reabsorption, rapidly accelerating the renal excretion of bromide.
Available products
Formulations
- 325 mg tablets
- 100 mg capsules
- 250 mg capsules
- 1000 mg capsules
- 250 mg/ml oral solution
Veterinary
- Bromilep
- Epilease
- Libromide
- Potassium bromide solution
Regulatory status
POM-V, AVM-GSL
POM-V, AVM-GSL
No regulatory data for: 🇺🇸 US · 🇭🇰 HK · 🇹🇼 TW · 🇯🇵 JP · 🇰🇷 KR · 🇦🇺 AU
Storage & stability
Normal precautions should be observed. Store in a cool, dry place away from direct sunlight.
Client information
Important Information for Pet Owners:
- Dietary Consistency is Crucial: The amount of salt in your dog's diet directly affects how this medication works. Do not change your dog's food, and be very careful with treats or table scraps. A sudden increase in salt will cause the drug to be flushed out of the body, potentially leading to seizures.
- Patience is Needed: This drug takes a very long time (up to 3-4 months) to reach its full, stable effect in the body unless your vet uses a high "loading dose" initially.
- Side Effects: Increased thirst, increased appetite, and increased urination are common. During the first few weeks, or if a loading dose is used, your dog may appear very sleepy, wobbly, or uncoordinated. Contact your vet if this is severe.
- NEVER GIVE TO CATS: This medication is highly toxic to cats and can cause a fatal lung condition.
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.