Potassium Bromide


Background

Potassium bromide is a reliable anti-convulsant (anti-seizure) medication in dogs. When compared to phenobarbital, potassium bromide seems to be similarly effective and have fewer undesirable side effects.

Potassium bromide works by competing with chloride ions for access to brain tissues. As bromide levels in the brain rise and chloride levels drop, electrical activity in the central nervous system is inhibited, making the initiation of a seizure difficult.This medication is generally reserved for dogs who cannot tolerate phenobarbital for seizures control due to unacceptable side effects or lack of effectiveness.

When potassium bromide therapy is initiated in a patient, it is common to begin with a loading dose, which is a high dose given for a short period of time to get the blood level up more quickly. It takes 3-4 months to get a stable bromide blood level.

Side Effects

  • Some nausea is associated with the administration of potassium bromide. Giving the medication with food generally controls this symptom.
  • Since potassium bromide is a salt, excess thirst and urination can be observed with this medication.
  • Occasionally a dog will develop a cough, which resolves when potassium bromide is discontinued.
  • In human beings, a toxicity syndrome called Bromism results when blood bromide levels become too high. Symptoms include drowsiness, weakness, muscle tremors, appetite loss, constipation, and skin rashes. Thus, bromide levels are monitored periodically. A similar syndrome can occur in dogs if bromide levels become too high.
  • Dogs with a history of pancreatitis may experience an exacerbation if potassium bromide is used to treat a seizure disorder. This is particularly true for patients taking both bromide and phenobarbital.

Cautions and Concerns

  • Potassium bromide should be given with food.
  • The administration of potassium bromide interferes with laboratory measurement of chloride, thus any tests for chloride will be falsely elevated.
  • Drowsiness or grogginess, which can be marked, is not abnormal during a loading period when potassium bromide therapy is started. It is important not to give more potassium bromide to a groggy pet even if another dose is due.

Veterinarian’s Comment

Potassium bromide is not a good choice for seizure control in cats. Over 1/3rd of feline patients develop a severe asthma-like lung condition with this medication.