Abnormal adrenocorticotropic hormone (acth) stimulation test after Levothyroxine in dogs

26 reports to the FDA describe abnormal adrenocorticotropic hormone (acth) stimulation test in dogs given Levothyroxine. That is 0.9% of all reports for this medicine, compared with 0.1% across reports for all dog medicines, so it is reported unusually often with this medicine.

26Reports
58%Marked serious
3.8%Recovered
12%Died or euthanised
102 daysTypical onset
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How soon it started

Same day
0 0.0%
1–2 days
0 0.0%
3–7 days
0 0.0%
1–4 weeks
0 0.0%
Over a month
15 100%

How the animals did

Recovered
1 3.8%
Still unwell when reported
8 31%
Euthanised
3 12%
Not known
14 54%

Problems reported at the same time

Hypoadrenocorticism
17 65%
Loss of appetite
11 42%
Lethargy
9 35%
Weight loss
7 27%
Didn't work as expected
6 23%
Excessive thirst
6 23%
Excessive urination
6 23%
Liver problems
6 23%

Age of the animals

Under 1 year
0
1–3 years
0
4–7 years
1
8–11 years
17
12+ years
8

About this medicine

Levothyroxine treats an underactive thyroid.

Questions owners ask

Can Levothyroxine cause abnormal adrenocorticotropic hormone (acth) stimulation test in dogs?
26 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 102 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).

Abnormal adrenocorticotropic hormone (acth) stimulation test with similar medicines

All reported side effects of Levothyroxine in dogs · Medicines most reported with abnormal adrenocorticotropic hormone (acth) stimulation test