Didn't prevent heartworm after Amoxicillin in dogs

21 reports to the FDA describe didn't prevent heartworm in dogs given Amoxicillin. That is 1.6% of all reports for this medicine, compared with 13% across reports for all dog medicines, so it is reported less often than average with this medicine.

21Reports

33%Marked serious

4.8%Recovered

0.0%Died or euthanised

131 daysTypical onset

How soon it started

Same day

2 17%

1–2 days

0 0.0%

3–7 days

0 0.0%

1–4 weeks

2 17%

Over a month

8 67%

How the animals did

Recovered

1 4.8%

Still unwell when reported

6 29%

Not known

14 67%

Problems reported at the same time

Otitis externa

4 19%

Didn't work as expected

4 19%

3 14%

3 14%

2 9.5%

2 9.5%

2 9.5%

Weight gain

2 9.5%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Amoxicillin treats bacterial infections.

Questions owners ask

Can Amoxicillin cause didn't prevent heartworm in dogs?: 21 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 131 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).

Didn't prevent heartworm with similar medicines

Didn't prevent heartworm after Amoxicillin + Clavulanate (Clavamox) 28 reports · 0.5% of its reports
Didn't prevent heartworm after Doxycycline 1,398 reports · 35% of its reports
Didn't prevent heartworm after Metronidazole 36 reports · 1.2% of its reports

All reported side effects of Amoxicillin in dogs · Medicines most reported with didn't prevent heartworm