Swollen mouth after Ivermectin + Praziquantel in horses

300 reports to the FDA describe swollen mouth in horses given Ivermectin + Praziquantel. That is 11% of all reports for this medicine, compared with 1.7% across reports for all horse medicines, so it is reported unusually often with this medicine.

300Reports

66%Marked serious

43%Recovered

0.0%Died or euthanised

Same dayTypical onset

How soon it started

Same day

146 76%

1–2 days

5 2.6%

3–7 days

0 0.0%

1–4 weeks

0 0.0%

Over a month

40 21%

How the animals did

Recovered

128 43%

Recovered with lasting effects

1 0.3%

Still unwell when reported

15 5.0%

Not known

156 52%

Problems reported at the same time

127 42%

77 26%

58 19%

57 19%

Application site reaction

54 18%

Skin redness

45 15%

Swollen tongue

43 14%

Loss of appetite

31 10%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

154

About this medicine

Ivermectin prevents heartworm disease (monthly). Praziquantel treats tapeworms.

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 Ivermectin + Praziquantel cause swollen mouth in horses?: 300 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).

All reported side effects of Ivermectin + Praziquantel in horses · Medicines most reported with swollen mouth