Unwell after Milbemycin Oxime + Praziquantel (Interceptor Plus) in dogs

35 reports to the FDA describe unwell in dogs given Milbemycin Oxime + Praziquantel. That is 0.1% of all reports for this medicine, compared with 0.1% across reports for all dog medicines, so it is reported unusually often with this medicine.

35Reports
17%Marked serious
8.6%Recovered
11%Died or euthanised
42 daysTypical onset
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How soon it started

Same day
7 25%
1–2 days
2 7.1%
3–7 days
0 0.0%
1–4 weeks
3 11%
Over a month
16 57%

How the animals did

Recovered
3 8.6%
Still unwell when reported
10 29%
Died
2 5.7%
Euthanised
2 5.7%
Not known
18 51%

Problems reported at the same time

Age of the animals

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

About this medicine

Milbemycin Oxime prevents heartworm and controls some intestinal worms (monthly). Praziquantel treats tapeworms.

Products with this combination include Interceptor Plus. 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 Milbemycin Oxime + Praziquantel cause unwell in dogs?
35 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 42 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).

All reported side effects of Milbemycin Oxime + Praziquantel in dogs · Medicines most reported with unwell