Loose stool after Ivermectin + Praziquantel in horses

The FDA has received 42 reports of loose stool in horses after Ivermectin + Praziquantel. That is 1.6% of all reports for this medicine, compared with 1.1% across reports for all horse medicines.

42Reports

12%Marked serious

7.1%Recovered

2.4%Died or euthanised

–Typical onset

How the animals did

Recovered

3 7.1%

Died

1 2.4%

Not known

38 90%

Problems reported at the same time

12 29%

10 24%

8 19%

8 19%

Didn't work as expected

3 7.1%

Dehydration

2 4.8%

Itching

2 4.8%

Liver problems

2 4.8%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

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 loose stool in horses?: 42 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.
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 loose stool