Lethargy after Mirtazapine (Mirataz) in dogs

95 reports to the FDA describe lethargy in dogs given Mirtazapine. That is 33% of all reports for this medicine, compared with 11% across reports for all dog medicines, so it is reported unusually often with this medicine.

95Reports

79%Marked serious

14%Recovered

42%Died or euthanised

14 daysTypical onset

How soon it started

Same day

13 16%

1–2 days

9 11%

3–7 days

6 7.6%

1–4 weeks

24 30%

Over a month

27 34%

How the animals did

Recovered

13 14%

Still unwell when reported

37 39%

Died

9 9.5%

Euthanised

31 33%

Not known

5 5.3%

Problems reported at the same time

75 79%

47 49%

44 46%

42 44%

30 32%

Abnormal ultrasound finding

27 28%

Diarrhea

23 24%

Weight loss

22 23%

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 lethargy in dogs?: 95 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 14 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).

Lethargy with similar medicines

Lethargy after Maropitant (Cerenia) 3,148 reports · 26% of its reports
Lethargy after Capromorelin (Entyce) 361 reports · 24% of its reports

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