Potassium bromide in dogs: dietary salt and seizures
6-year-old Golden Retriever, seizure-free for 2 years on potassium bromide monotherapy with stable levels. A month ago the owners changed its food and began giving it cured meats as treats. It has had three seizures in the last two weeks.
What is the most likely explanation?
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A. Higher dietary chloride increases renal bromide excretion and its levels fall
Correct. Chloride and bromide compete for tubular reabsorption, so more salt means more bromide excretion. Measure levels, return to a consistent diet and adjust the dose.
B. Tolerance to bromide has developed
Tolerance does not explain a sudden worsening linked to a diet change. Levels must be measured before talking about tolerance or drug resistance.
C. Dietary sodium directly lowers the seizure threshold
The relevant effect is not sodium on the threshold but chloride on bromide elimination.
D. The new food induces the hepatic enzymes that metabolise bromide
Bromide is not metabolised by the liver; it is excreted unchanged by the kidney.
lightbulb Key takeaway
Bromide has a very long half-life in dogs (about 3–4 weeks) and takes about 3 months to reach steady state unless a loading dose is used. Keep diet and treats consistent. It can cause polyphagia, PU/PD, ataxia and vomiting, has been linked to pancreatitis and gives a spurious hyperchloraemia on many analysers.
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Updated: October 31, 2026 · Educational content for veterinary professionals. It does not replace current clinical guidelines or the judgement of the attending veterinarian.