Didn't stop ticks after Eprinomectin + Esafoxolaner + Praziquantel (NexGard Combo) in cats

The FDA has received 31 reports of didn't stop ticks in cats after Eprinomectin + Esafoxolaner + Praziquantel. That is 1.0% of all reports for this medicine, compared with 0.5% across reports for all cat medicines, so it is reported unusually often with this medicine.

31Reports
16%Marked serious
26%Recovered
6.5%Died or euthanised
12 daysTypical onset
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How soon it started

Same day
2 7.1%
1–2 days
4 14%
3–7 days
5 18%
1–4 weeks
14 50%
Over a month
3 11%

How the animals did

Recovered
8 26%
Still unwell when reported
4 13%
Died
1 3.2%
Euthanised
1 3.2%
Not known
17 55%

Problems reported at the same time

Age of the animals

Under 1 year
4
1–3 years
11
4–7 years
6
8–11 years
4
12+ years
1

About this medicine

Eprinomectin controls worms and prevents heartworm. Esafoxolaner kills fleas and ticks (spot-on for cats). Praziquantel treats tapeworms.

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

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 + Esafoxolaner + Praziquantel cause didn't stop ticks in cats?
31 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 12 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 ticks with similar medicines

All reported side effects of Eprinomectin + Esafoxolaner + Praziquantel in cats · Medicines most reported with didn't stop ticks