Diarrhea after Mirtazapine (Mirataz) in dogs

The FDA has received 59 reports of diarrhea in dogs after Mirtazapine. That is 20% of all reports for this medicine, compared with 8.4% across reports for all dog medicines, so it is reported unusually often with this medicine.

59Reports

83%Marked serious

10%Recovered

46%Died or euthanised

17 daysTypical onset

How soon it started

Same day

8 15%

1–2 days

9 17%

3–7 days

6 11%

1–4 weeks

11 21%

Over a month

19 36%

How the animals did

Recovered

6 10%

Still unwell when reported

21 36%

Died

7 12%

Euthanised

20 34%

Not known

5 8.5%

Problems reported at the same time

47 80%

37 63%

26 44%

25 42%

23 39%

21 36%

Abnormal ultrasound finding

14 24%

Blood problems

13 22%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Mirtazapine stimulates appetite (cats: ointment applied to the ear).

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

Questions owners ask

Can Mirtazapine cause diarrhea in dogs?: 59 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 17 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).

Diarrhea with similar medicines

Diarrhea after Maropitant (Cerenia) 2,143 reports · 18% of its reports
Diarrhea after Capromorelin (Entyce) 195 reports · 13% of its reports

All reported side effects of Mirtazapine in dogs · Medicines most reported with diarrhea