Hypochloraemia after Fluralaner (Bravecto) in dogs

The FDA has received 106 reports of hypochloraemia in dogs after Fluralaner. That is 0.2% of all reports for this medicine, compared with 0.2% across reports for all dog medicines.

106Reports
95%Marked serious
7.5%Recovered
36%Died or euthanised
2 daysTypical onset
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How soon it started

Same day
17 27%
1–2 days
17 27%
3–7 days
7 11%
1–4 weeks
4 6.3%
Over a month
18 29%

How the animals did

Recovered
2 1.9%
Recovered with lasting effects
6 5.7%
Still unwell when reported
45 42%
Died
18 17%
Euthanised
20 19%
Not known
15 14%

Problems reported at the same time

Age of the animals

Under 1 year
7
1–3 years
21
4–7 years
34
8–11 years
28
12+ years
16

About this medicine

Fluralaner kills fleas and ticks for up to 12 weeks (chewable or spot-on).

Products with this ingredient include Bravecto. The FDA hides brand names in its public data, so these reports cover every product with the same active ingredients.

In 2018 the FDA alerted owners and vets that isoxazoline products have been associated with neurologic reactions such as muscle tremors, wobbliness (ataxia) and seizures, including in animals with no history of them.

Questions owners ask

Can Fluralaner cause hypochloraemia in dogs?
106 reports link the two, but a report alone does not prove the medicine was the cause: other illnesses, other medicines or coincidence can be involved. Your vet can judge it for your animal.
How soon after a dose was it reported?
In half of the reports with dates, it started within 2 days of the first dose.
What should I do?
Don't give another dose until you've spoken to your vet, and keep the packaging so you can tell them the product and dose. Your vet can also report it to the FDA (or you can, through the manufacturer or FDA form 1932a).

Hypochloraemia with similar medicines

All reported side effects of Fluralaner in dogs · Medicines most reported with hypochloraemia