Skin rash or irritation after Amitraz + Fipronil + S-methoprene in dogs

The FDA has received 20 reports of skin rash or irritation in dogs after Amitraz + Fipronil + S-methoprene. That is 4.3% of all reports for this medicine, compared with 1.3% across reports for all dog medicines, so it is reported unusually often with this medicine.

20Reports

90%Marked serious

30%Recovered

10%Died or euthanised

56 daysTypical onset

How soon it started

Same day

0 0.0%

1–2 days

1 9.1%

3–7 days

0 0.0%

1–4 weeks

2 18%

Over a month

8 73%

How the animals did

Recovered

5 25%

Recovered with lasting effects

1 5.0%

Still unwell when reported

4 20%

Euthanised

2 10%

Not known

8 40%

Problems reported at the same time

Hair loss

9 45%

Application site reaction

8 40%

Skin redness

6 30%

Lethargy

5 25%

Pemphigus foliaceus

5 25%

Bacterial skin infection

5 25%

Itching

4 20%

Pr-skin, lesion(s)

4 20%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Fipronil kills fleas and ticks (spot-on).

Questions owners ask

Can Amitraz + Fipronil + S-methoprene cause skin rash or irritation in dogs?: 20 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 56 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).

Skin rash or irritation with similar medicines

Skin rash or irritation after Spinosad (Comfortis) 726 reports · 1.3% of its reports
Skin rash or irritation after Lufenuron + Milbemycin Oxime (Sentinel) 344 reports · 1.3% of its reports
Skin rash or irritation after Imidacloprid + Moxidectin (Advantage Multi) 504 reports · 3.8% of its reports
Skin rash or irritation after Nitenpyram (Capstar) 163 reports · 1.5% of its reports
Skin rash or irritation after Lufenuron + Milbemycin Oxime + Praziquantel (Sentinel Spectrum) 45 reports · 0.5% of its reports
Skin rash or irritation after Fipronil + S-methoprene (Frontline Plus) 62 reports · 2.1% of its reports
Skin rash or irritation after Flumethrin + Imidacloprid (Seresto) 103 reports · 4.5% of its reports
Skin rash or irritation after Imidacloprid 44 reports · 2.3% of its reports
Skin rash or irritation after Fipronil 30 reports · 2.1% of its reports
Skin rash or irritation after Lufenuron 60 reports · 5.9% of its reports

All reported side effects of Amitraz + Fipronil + S-methoprene in dogs · Medicines most reported with skin rash or irritation