Potassium Bromide for Veterinary Use

Basic Information

Potassium bromide acts at the cellular level to decrease seizure activity by depressing neuronal activity and excitability. Potassium bromide is well absorbed orally and is excreted principally by the kidneys.

Dogs and Cats

Potassium bromide is an antiepileptic drug (AED) used in dogs to control seizures that are not controlled adequately by phenobarbital alone. Potassium bromide is almost always used initially in conjunction with phenobarbital and rarely is considered as a first-line drug because it may take as long as four months to reach a steady state concentration of bromide in the brain.

Managing animals with seizure disorders requires measurement of serum trough concentrations of AED at regular intervals in order to tailor a therapeutic dose for the individual patient and to minimize the occurrence of toxicity. Once a steady state serum concentration of potassium bromide has been reached, some clinicians may attempt to reduce the dose or even eliminate phenobarbital in those patients whose seizures are well controlled. Dogs that are suffering from hepatotoxicity due to phenobarbital may be treated with potassium bromide alone because of its renal excretion.

Cats are treated only rarely with potassium bromide because of the relatively high incidence of side effects in this species.

Client commitment and compliance are essential for managing animals with seizure disorders. Because both phenobarbital and potassium bromide can be sedating, clients need to understand that their pets may have a less active lifestyle. The client will need to administer medication at prescribed regular intervals and the animal will need regular blood work to monitor serum drug levels.

Potassium Bromide Side Effects

Transient sedation, lethargy, anorexia, vomiting, polydipsia, polyuria, pancreatitis, constipation.

Precautions

• Chloride ion levels affect bromide levels because they compete for uptake across the cellular membrane. Bromide toxicity can occur in animals that are placed on restricted sodium intake such as a low-salt diet. On the other hand, increased sodium intake will decrease bromide levels, placing the animal at risk for a seizure.
• The reproductive safety of bromide use in dogs has not been established. Bromide both crosses the placenta and is found in milk of lactating humans.
• Older animals may have a higher incidence of adverse side-effects.

Drug Interactions

• Diuretics such as furosemide will increase the excretion of potassium bromide.
• Other CNS-sedating drugs may cause additional sedation when used with potassium bromide.

Overdose

• Bromism or toxicity due to chronic overdose presents as profound sedation, muscle pain, CNS signs, ataxia, stupor, and tremors.
• Acute overdose occurs less frequently, but may present similarly to chronic overdose with profound sedation, ataxia and other CNS signs. Treatment may include GI emptying, supportive use of IV fluids and diuretics.