Loss of appetite after Milbemycin Oxime + Praziquantel (Interceptor Plus) in dogs

The FDA has received 1,598 reports of loss of appetite in dogs after Milbemycin Oxime + Praziquantel. That is 5.1% of all reports for this medicine, compared with 8.4% across reports for all dog medicines, so it is reported less often than average with this medicine.

1,598Reports
28%Marked serious
30%Recovered
7.1%Died or euthanised
2 daysTypical onset
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How soon it started

Same day
370 32%
1–2 days
220 19%
3–7 days
69 5.9%
1–4 weeks
107 9.1%
Over a month
407 35%

How the animals did

Recovered
479 30%
Recovered with lasting effects
3 0.2%
Still unwell when reported
555 35%
Died
42 2.6%
Euthanised
71 4.4%
Not known
448 28%

Problems reported at the same time

813 51%
737 46%
482 30%
142 8.9%
137 8.6%

Age of the animals

Under 1 year
251
1–3 years
418
4–7 years
395
8–11 years
311
12+ years
187

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 loss of appetite in dogs?
1,598 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 2 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).

Loss of appetite with similar medicines

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