Milbemycin Oxime (Interceptor) side effects in dogs
29,766 reports sent to the FDA between 1995 and 2026 involve Milbemycin Oxime in dogs. The most reported problems were vomiting, diarrhea, lethargy. 10% were marked serious, and where it was recorded, signs eased after stopping the medicine in 7% of cases.
About this medicine
Milbemycin Oxime prevents heartworm and controls some intestinal worms (monthly).
Products with this ingredient include Interceptor. 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.
Most reported side effects
Share = percentage of this medicine's reports that mention the problem. One report can list several problems.
Reports that it didn't work
Some reports are about the medicine not working (for example a dog still getting fleas or heartworm), not about a side effect.
How soon problems started
Time from the first dose to the first sign, where both dates were reported (3,733 reports).
How the animals did
Breeds named most often
Popular breeds appear more often because there are more of them.
- Labrador Retriever 4,732 reports
- German Shepherd Dog 1,344 reports
- Golden Retriever 1,147 reports
- Beagle 724 reports
- Boxer (german Boxer) 668 reports
- Dachshund 544 reports
- Yorkshire Terrier 534 reports
- Chihuahua 486 reports
- Australian Shepherd Dog 469 reports
- Shetland Sheepdog 402 reports