Didn't stop worms after Praziquantel in dogs

The FDA has received 403 reports of didn't stop worms in dogs after Praziquantel. That is 36% 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.

403Reports
33%Marked serious
12%Recovered
0.7%Died or euthanised
17 daysTypical onset
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How soon it started

Same day
21 7.8%
1–2 days
37 14%
3–7 days
43 16%
1–4 weeks
77 29%
Over a month
90 34%

How the animals did

Recovered
49 12%
Still unwell when reported
26 6.5%
Died
2 0.5%
Euthanised
1 0.2%
Not known
325 81%

Problems reported at the same time

Overdose
50 12%
Diarrhea
29 7.2%
Vomiting
27 6.7%
Didn't work as expected
18 4.5%
Lethargy
12 3.0%
Loss of appetite
10 2.5%
Underdose
10 2.5%
Weight gain
6 1.5%

Age of the animals

Under 1 year
159
1–3 years
86
4–7 years
50
8–11 years
33
12+ years
24

About this medicine

Praziquantel treats tapeworms.

Questions owners ask

Can Praziquantel cause didn't stop worms in dogs?
403 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).

Didn't stop worms with similar medicines

All reported side effects of Praziquantel in dogs · Medicines most reported with didn't stop worms