Potassium Bromide

Potassium bromide In Dogs & Cats: Uses, Dosage and Side Effects

Overview

• Within the central nervous system (CNS), bromide competes with transmembrane chloride transport and inhibits sodium.
• This action leads to membrane hyperpolarization and an increase in the seizure threshold.
• Bromide competes with chloride in post-synaptic anion channels activated by inhibitory neurotransmitters, enhancing the effect of GABA.
• It acts synergistically with other therapeutic agents that have GABA-ergic effects, such as phenobarbital

Uses of Potassium bromide

Dose of Potassium bromide in Dogs and Cats

Dogs:

• The initial daily maintenance dose is 20–40 mg/kg p.o q24h.
• It is not necessary to dose more frequently, but more frequent dosing is not detrimental.
• The loading dose is 200 mg/kg/day p.o. divided into 4–6 hour doses for 5 days, after which the dose is decreased to the maintenance dose (20–40 mg/kg p.o. q24h).
• If seizures resolve sooner, it is advisable to decrease the loading dose to maintenance levels earlier to reduce adverse effects.
• A single loading dose of 600–1000 mg/kg p.o. can be given but this is likely
  to result in excessive sedation, ataxia and potentially vomiting.
• Intrarectal bromide can be loaded over 24 hours.
• The loading schedule for liquid bromide (250 mg/ml) by rectum is 100 mg/kg q4h for 6 doses (total 600 mg/kg).

Cats:

• Do not use.

Side Effects of Potassium bromide in Dogs and Cats

• Overdosage and loading doses of potassium bromide (KBr) can result in ataxia, sedation, and somnolence.
• Animals with pre-existing skin diseases, like flea bite dermatitis, may experience skin reactions.
• Vomiting is a potential side effect after oral administration, especially with high concentrations (>250 mg/ml).
• Other reported effects include polyphagia, polydipsia, and pancreatitis.
• In cases of acute bromide toxicity, intravenous administration of 0.9% NaCl is the preferred treatment.
• Behavioural changes, such as irritability or restlessness, may be observed less frequently.

Contraindications of Potassium bromide in Dogs and Cats

• Do not use in the cat due to the development of severe coughing due to eosinophilic bronchitis, which may be fatal.
• Avoid use in dogs with a history, or a predisposition for the development, of pancreatitis.

Some Notes:

• Bromide competes with chloride for renal reabsorption.
• Increased dietary salt, administration of fluids or drugs containing chloride, and use of loop diuretics (e.g. furosemide) may result in increased bromide excretion and decreased serum bromide concentrations.
• Bromide, with a long half-life (>20 days), may take 3–4 months to achieve steady-state plasma concentrations.
• Monitoring of serum drug concentrations is crucial, aiming for a therapeutic range of 0.8–1.5 mg/ml.
• Loading doses may be necessary for rapid therapeutic levels, but they are linked to increased adverse effects and should be reserved for dogs with poorly controlled severe seizures.
• Enema administration is an option for unconscious dogs, but it may result in increased sedation and transient diarrhoea.
• Serum samples post-loading dose are advised to assess serum concentration.
• Bromide’s slow rise in plasma levels after oral administration limits its utility in status epilepticus.
• Absorbed well in the GI tract, bromide is slowly eliminated by the kidney, competing with chloride; dietary salt levels can affect renal elimination.
• Diet should remain constant during bromide therapy, and caution is advised in dogs with renal disease.
• Bromide measurements in assays for chloride may yield falsely high ‘chloride’ results.