Drug dose administration interval too long after Moxidectin (ProHeart 6) in dogs

The FDA has received 587 reports of drug dose administration interval too long in dogs after Moxidectin. That is 1.2% of all reports for this medicine, compared with 0.3% across reports for all dog medicines, so it is reported unusually often with this medicine.

587Reports
84%Marked serious
2.7%Recovered
0.2%Died or euthanised
250 daysTypical onset
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How soon it started

Same day
8 7.9%
1–2 days
1 1.0%
3–7 days
3 3.0%
1–4 weeks
0 0.0%
Over a month
89 88%

How the animals did

Recovered
16 2.7%
Still unwell when reported
554 94%
Died
1 0.2%
Not known
16 2.7%

Problems reported at the same time

Age of the animals

Under 1 year
2
1–3 years
243
4–7 years
213
8–11 years
98
12+ years
27

About this medicine

Moxidectin prevents heartworm disease (monthly topical, or a 6- or 12-month injection for dogs).

Products with this ingredient include ProHeart 6, ProHeart 12. 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 Moxidectin cause drug dose administration interval too long in dogs?
587 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 250 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).

Drug dose administration interval too long with similar medicines

All reported side effects of Moxidectin in dogs · Medicines most reported with drug dose administration interval too long