Seizures after Moxidectin (ProHeart 6) in dogs

2,058 reports to the FDA describe seizures in dogs given Moxidectin. That is 4.1% of all reports for this medicine, compared with 4.4% across reports for all dog medicines.

2,058Reports

58%Marked serious

16%Recovered

16%Died or euthanised

2 daysTypical onset

How soon it started

Same day

428 35%

1–2 days

227 19%

3–7 days

165 14%

1–4 weeks

183 15%

Over a month

219 18%

How the animals did

Recovered

327 16%

Recovered with lasting effects

3 0.1%

Still unwell when reported

722 35%

Died

254 12%

Euthanised

81 3.9%

Not known

671 33%

Problems reported at the same time

331 16%

293 14%

265 13%

182 8.8%

177 8.6%

163 7.9%

156 7.6%

145 7.0%

Age of the animals

Under 1 year

1–3 years

714

4–7 years

675

8–11 years

344

12+ years

163

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 seizures in dogs?: 2,058 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).

Seizures with similar medicines

Seizures after Ivermectin + Pyrantel (Heartgard Plus) 3,287 reports · 2.2% of its reports
Seizures after Milbemycin Oxime + Spinosad (Trifexis) 4,483 reports · 3.5% of its reports
Seizures after Milbemycin Oxime + Praziquantel (Interceptor Plus) 945 reports · 3.0% of its reports
Seizures after Milbemycin Oxime (Interceptor) 1,089 reports · 3.7% of its reports
Seizures after Selamectin (Revolution) 1,272 reports · 4.3% of its reports
Seizures after Ivermectin (Heartgard) 686 reports · 5.7% of its reports
Seizures after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 196 reports · 2.3% of its reports
Seizures after Moxidectin + Pyrantel + Sarolaner (Simparica Trio) 90 reports · 7.8% of its reports
Seizures after Ivermectin + Praziquantel 22 reports · 11% of its reports

All reported side effects of Moxidectin in dogs · Medicines most reported with seizures