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

The FDA has received 763 reports of itching in dogs after Milbemycin Oxime + Praziquantel. That is 2.4% of all reports for this medicine, compared with 4.3% across reports for all dog medicines, so it is reported less often than average with this medicine.

763Reports
15%Marked serious
24%Recovered
1.7%Died or euthanised
6 daysTypical onset
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How soon it started

Same day
171 30%
1–2 days
85 15%
3–7 days
32 5.7%
1–4 weeks
60 11%
Over a month
218 39%

How the animals did

Recovered
182 24%
Recovered with lasting effects
4 0.5%
Still unwell when reported
305 40%
Died
6 0.8%
Euthanised
7 0.9%
Not known
259 34%

Problems reported at the same time

Age of the animals

Under 1 year
110
1–3 years
234
4–7 years
206
8–11 years
135
12+ years
51

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 itching in dogs?
763 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 6 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).

Itching with similar medicines

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