Swelling after Moxidectin (ProHeart 6) in dogs

The FDA has received 7,913 reports of swelling in dogs after Moxidectin. That is 16% of all reports for this medicine, compared with 2.8% across reports for all dog medicines, so it is reported unusually often with this medicine.

7,913Reports

42%Marked serious

35%Recovered

2.7%Died or euthanised

Same dayTypical onset

How soon it started

Same day

5,298 88%

1–2 days

297 5.0%

3–7 days

154 2.6%

1–4 weeks

135 2.3%

Over a month

112 1.9%

How the animals did

Recovered

2,748 35%

Recovered with lasting effects

2 0.0%

Still unwell when reported

2,962 37%

Died

165 2.1%

Euthanised

50 0.6%

Not known

1,986 25%

Problems reported at the same time

4,954 63%

2,898 37%

1,026 13%

1,019 13%

688 8.7%

555 7.0%

550 7.0%

546 6.9%

Age of the animals

Under 1 year

967

1–3 years

4,306

4–7 years

1,792

8–11 years

594

12+ years

142

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 swelling in dogs?: 7,913 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 the same day 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).

Swelling with similar medicines

Swelling after Ivermectin + Pyrantel (Heartgard Plus) 839 reports · 0.6% of its reports
Swelling after Milbemycin Oxime + Spinosad (Trifexis) 959 reports · 0.7% of its reports
Swelling after Milbemycin Oxime + Praziquantel (Interceptor Plus) 371 reports · 1.2% of its reports
Swelling after Milbemycin Oxime (Interceptor) 257 reports · 0.9% of its reports
Swelling after Selamectin (Revolution) 410 reports · 1.4% of its reports
Swelling after Ivermectin (Heartgard) 204 reports · 1.7% of its reports
Swelling after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 66 reports · 0.8% of its reports
Swelling after Moxidectin + Pyrantel + Sarolaner (Simparica Trio) 22 reports · 1.9% of its reports

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