Elevated gamma-glutamyl transferase (ggt) after Ivermectin (Heartgard) in dogs

32 reports to the FDA describe elevated gamma-glutamyl transferase (ggt) in dogs given Ivermectin. That is 0.3% of all reports for this medicine, compared with 0.4% across reports for all dog medicines.

32Reports
69%Marked serious
9.4%Recovered
34%Died or euthanised
63 daysTypical onset
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How soon it started

Same day
2 11%
1–2 days
1 5.3%
3–7 days
1 5.3%
1–4 weeks
3 16%
Over a month
12 63%

How the animals did

Recovered
1 3.1%
Recovered with lasting effects
2 6.3%
Still unwell when reported
11 34%
Died
1 3.1%
Euthanised
10 31%
Not known
7 22%

Problems reported at the same time

Liver problems
31 97%
Loss of appetite
19 59%
Vomiting
17 53%
Lethargy
15 47%
Kidney problems
12 38%
Death
11 34%
Breathing problems
10 31%
Leucocytosis
9 28%

Age of the animals

Under 1 year
2
1–3 years
2
4–7 years
9
8–11 years
15
12+ years
3

About this medicine

Ivermectin prevents heartworm disease (monthly).

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

Some herding breeds (for example Collies) carry the MDR1 gene variant and can be more sensitive to this drug class at high doses.

Questions owners ask

Can Ivermectin cause elevated gamma-glutamyl transferase (ggt) in dogs?
32 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 63 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).

Elevated gamma-glutamyl transferase (ggt) with similar medicines

All reported side effects of Ivermectin in dogs · Medicines most reported with elevated gamma-glutamyl transferase (ggt)