Diarrhea after Ivermectin + Praziquantel in horses

The FDA has received 122 reports of diarrhea in horses after Ivermectin + Praziquantel. That is 4.6% of all reports for this medicine, compared with 4.9% across reports for all horse medicines.

122Reports

11%Marked serious

8.2%Recovered

11%Died or euthanised

Same dayTypical onset

How soon it started

Same day

11 61%

1–2 days

6 33%

3–7 days

0 0.0%

1–4 weeks

0 0.0%

Over a month

1 5.6%

How the animals did

Recovered

10 8.2%

Still unwell when reported

1 0.8%

Died

11 9.0%

Euthanised

2 1.6%

Not known

98 80%

Problems reported at the same time

32 26%

31 25%

21 17%

13 11%

8 6.6%

Dehydration

8 6.6%

Loose stool

8 6.6%

Swelling

7 5.7%

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 diarrhea in horses?: 122 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).

Diarrhea with similar medicines

Diarrhea after Moxidectin (ProHeart 6) 76 reports · 5.6% of its reports
Diarrhea after Ivermectin (Heartgard) 52 reports · 7.5% of its reports
Diarrhea after Moxidectin + Praziquantel 37 reports · 9.9% of its reports

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