Didn't stop worms after Pyrantel in cats

The FDA has received 51 reports of didn't stop worms in cats after Pyrantel. That is 9.1% of all reports for this medicine, compared with 1.8% across reports for all cat medicines, so it is reported unusually often with this medicine.

51Reports
22%Marked serious
3.9%Recovered
2.0%Died or euthanised
25 daysTypical onset
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How soon it started

Same day
1 2.7%
1–2 days
3 8.1%
3–7 days
7 19%
1–4 weeks
10 27%
Over a month
16 43%

How the animals did

Recovered
2 3.9%
Still unwell when reported
14 27%
Died
1 2.0%
Not known
34 67%

Problems reported at the same time

Diarrhea
4 7.8%
Didn't work as expected
4 7.8%
Drug administration error
4 7.8%
Vomiting
4 7.8%
Drug dose administration interval too short
2 3.9%
Drug dose administration interval too long
2 3.9%
Death
1 2.0%
Sneezing
1 2.0%

Age of the animals

Under 1 year
40
1–3 years
4
4–7 years
2
8–11 years
1
12+ years
0

About this medicine

Pyrantel treats roundworms and hookworms.

Questions owners ask

Can Pyrantel cause didn't stop worms in cats?
51 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 25 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 Pyrantel in cats · Medicines most reported with didn't stop worms