Didn't stop worms after Eprinomectin + Praziquantel in cats

The FDA has received 99 reports of didn't stop worms in cats after Eprinomectin + Praziquantel. That is 17% 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.

99Reports
0.0%Marked serious
4.0%Recovered
0.0%Died or euthanised
15 daysTypical onset
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How soon it started

Same day
6 6.5%
1–2 days
6 6.5%
3–7 days
10 11%
1–4 weeks
47 51%
Over a month
24 26%

How the animals did

Recovered
4 4.0%
Still unwell when reported
7 7.1%
Not known
88 89%

Problems reported at the same time

Vomiting
3 3.0%
Weight loss
3 3.0%
Drooling
2 2.0%
Drug dose administration interval too short
2 2.0%
Blood problems
2 2.0%
Liver problems
2 2.0%
Didn't stop fleas
2 2.0%
Skin lump
2 2.0%

Age of the animals

Under 1 year
47
1–3 years
18
4–7 years
5
8–11 years
5
12+ years
3

About this medicine

Eprinomectin controls worms and prevents heartworm. Praziquantel treats tapeworms.

Some herding breeds (for example Collies) carry the MDR1 gene variant and can be more sensitive to this drug class at high doses.

Questions owners ask

Can Eprinomectin + Praziquantel cause didn't stop worms in cats?
99 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 15 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 Eprinomectin + Praziquantel in cats · Medicines most reported with didn't stop worms