Fipronil + S-methoprene (Frontline Plus) side effects in dogs
2,954 reports sent to the FDA between 2011 and 2026 involve Fipronil + S-methoprene in dogs. The most reported problems were vomiting, lethargy, itching. 49% were marked serious.
About this medicine
Fipronil kills fleas and ticks (spot-on).
Products with this combination include Frontline Plus. The FDA hides brand names in its public data, so these reports cover every product with the same active ingredients.
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 (1,699 reports).
How the animals did
Breeds named most often
Popular breeds appear more often because there are more of them.
- Labrador Retriever 213 reports
- Golden Retriever 99 reports
- Shih Tzu 98 reports
- Yorkshire Terrier 86 reports
- German Shepherd Dog 79 reports
- Chihuahua 72 reports
- King Charles Cavalier Spaniel 66 reports
- Dog (other) 63 reports
- Australian Shepherd Dog 46 reports
- Boxer (german Boxer) 41 reports