Hair loss after Milbemycin Oxime + Praziquantel (Interceptor Plus) in dogs

The FDA has received 158 reports of hair loss in dogs after Milbemycin Oxime + Praziquantel. That is 0.5% of all reports for this medicine, compared with 1.0% across reports for all dog medicines, so it is reported less often than average with this medicine.

158Reports

15%Marked serious

7.6%Recovered

2.5%Died or euthanised

51 daysTypical onset

How soon it started

Same day

12 11%

1–2 days

10 9.0%

3–7 days

11 9.9%

1–4 weeks

18 16%

Over a month

60 54%

How the animals did

Recovered

12 7.6%

Still unwell when reported

76 48%

Died

1 0.6%

Euthanised

3 1.9%

Not known

66 42%

Problems reported at the same time

Itching

56 35%

Didn't prevent heartworm

23 15%

Lethargy

22 14%

Vomiting

19 12%

Didn't work as expected

18 11%

Skin rash or irritation

16 10%

Didn't stop worms

15 9.5%

Loss of appetite

15 9.5%

Age of the animals

Under 1 year

1–3 years

4–7 years

8–11 years

12+ years

About this medicine

Milbemycin Oxime prevents heartworm and controls some intestinal worms (monthly). Praziquantel treats tapeworms.

Products with this combination include Interceptor 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 Milbemycin Oxime + Praziquantel cause hair loss in dogs?: 158 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 51 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).

Hair loss with similar medicines

Hair loss after Ivermectin + Pyrantel (Heartgard Plus) 539 reports · 0.4% of its reports
Hair loss after Milbemycin Oxime + Spinosad (Trifexis) 1,029 reports · 0.8% of its reports
Hair loss after Moxidectin (ProHeart 6) 325 reports · 0.6% of its reports
Hair loss after Milbemycin Oxime (Interceptor) 132 reports · 0.4% of its reports
Hair loss after Selamectin (Revolution) 1,036 reports · 3.5% of its reports
Hair loss after Ivermectin (Heartgard) 104 reports · 0.9% of its reports
Hair loss after Ivermectin + Praziquantel + Pyrantel (Iverhart Max) 20 reports · 0.2% of its reports

All reported side effects of Milbemycin Oxime + Praziquantel in dogs · Medicines most reported with hair loss