Lymphopenia after Lufenuron + Milbemycin Oxime (Sentinel) in dogs

The FDA has received 25 reports of lymphopenia in dogs after Lufenuron + Milbemycin Oxime. That is 0.1% of all reports for this medicine, compared with 0.3% across reports for all dog medicines, so it is reported less often than average with this medicine.

25Reports
64%Marked serious
8.0%Recovered
20%Died or euthanised
21 daysTypical onset
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How soon it started

Same day
4 36%
1–2 days
0 0.0%
3–7 days
0 0.0%
1–4 weeks
4 36%
Over a month
3 27%

How the animals did

Recovered
2 8.0%
Still unwell when reported
4 16%
Died
5 20%
Not known
14 56%

Problems reported at the same time

Age of the animals

Under 1 year
1
1–3 years
3
4–7 years
8
8–11 years
10
12+ years
3

About this medicine

Lufenuron stops flea eggs from developing. Milbemycin Oxime prevents heartworm and controls some intestinal worms (monthly).

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

Questions owners ask

Can Lufenuron + Milbemycin Oxime cause lymphopenia in dogs?
25 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 21 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).

Lymphopenia with similar medicines

All reported side effects of Lufenuron + Milbemycin Oxime in dogs · Medicines most reported with lymphopenia