Inappropriate urination after Ivermectin + Pyrantel (Heartgard Plus) in dogs

352 reports to the FDA describe inappropriate urination in dogs given Ivermectin + Pyrantel. That is 0.2% of all reports for this medicine, compared with 0.5% across reports for all dog medicines, so it is reported less often than average with this medicine.

352Reports

62%Marked serious

36%Recovered

9.9%Died or euthanised

5 daysTypical onset

How soon it started

Same day

72 29%

1–2 days

42 17%

3–7 days

20 8.1%

1–4 weeks

43 17%

Over a month

70 28%

How the animals did

Recovered

121 34%

Recovered with lasting effects

6 1.7%

Still unwell when reported

50 14%

Died

16 4.5%

Euthanised

19 5.4%

Not known

140 40%

Problems reported at the same time

Seizures

128 36%

Lethargy

83 24%

Vomiting

73 21%

Inappropriate defecation

63 18%

58 16%

58 16%

47 13%

44 13%

Age of the animals

Under 1 year

1–3 years

110

4–7 years

8–11 years

12+ years

About this medicine

Ivermectin prevents heartworm disease (monthly). Pyrantel treats roundworms and hookworms.

Products with this combination include Heartgard Plus, Tri-Heart Plus, Iverhart Plus. 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 Ivermectin + Pyrantel cause inappropriate urination in dogs?: 352 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 5 days 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).

Inappropriate urination with similar medicines

Inappropriate urination after Milbemycin Oxime + Spinosad (Trifexis) 494 reports · 0.4% of its reports
Inappropriate urination after Moxidectin (ProHeart 6) 168 reports · 0.3% of its reports
Inappropriate urination after Milbemycin Oxime + Praziquantel (Interceptor Plus) 124 reports · 0.4% of its reports
Inappropriate urination after Milbemycin Oxime (Interceptor) 34 reports · 0.1% of its reports
Inappropriate urination after Selamectin (Revolution) 35 reports · 0.1% of its reports
Inappropriate urination after Ivermectin (Heartgard) 60 reports · 0.5% of its reports
Inappropriate urination after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 20 reports · 0.2% of its reports

All reported side effects of Ivermectin + Pyrantel in dogs · Medicines most reported with inappropriate urination