Loose stool after Selamectin (Revolution) in dogs

The FDA has received 156 reports of loose stool in dogs after Selamectin. That is 0.5% of all reports for this medicine, compared with 0.9% across reports for all dog medicines, so it is reported less often than average with this medicine.

156Reports

8.3%Marked serious

9.0%Recovered

3.2%Died or euthanised

1 daysTypical onset

How soon it started

Same day

24 40%

1–2 days

17 28%

3–7 days

6 10%

1–4 weeks

8 13%

Over a month

5 8.3%

How the animals did

Recovered

14 9.0%

Still unwell when reported

29 19%

Died

4 2.6%

Euthanised

1 0.6%

Not known

108 69%

Problems reported at the same time

53 34%

50 32%

45 29%

18 12%

16 10%

15 9.6%

Didn't work as expected

11 7.1%

Skin redness

8 5.1%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Selamectin prevents heartworm and treats fleas, ear mites and some worms (spot-on).

Products with this ingredient include Revolution. 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 Selamectin cause loose stool in dogs?: 156 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 1 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).

Loose stool with similar medicines

Loose stool after Ivermectin + Pyrantel (Heartgard Plus) 1,339 reports · 0.9% of its reports
Loose stool after Milbemycin Oxime + Spinosad (Trifexis) 885 reports · 0.7% of its reports
Loose stool after Moxidectin (ProHeart 6) 332 reports · 0.7% of its reports
Loose stool after Milbemycin Oxime + Praziquantel (Interceptor Plus) 406 reports · 1.3% of its reports
Loose stool after Milbemycin Oxime (Interceptor) 327 reports · 1.1% of its reports
Loose stool after Ivermectin (Heartgard) 88 reports · 0.7% of its reports
Loose stool after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 120 reports · 1.4% of its reports

All reported side effects of Selamectin in dogs · Medicines most reported with loose stool