When does the action of flea drops begin? - briefly
The flea‑drop effect starts almost immediately, usually within 5–10 minutes after the product contacts the animal’s skin, and reaches its peak efficacy in about 30–60 minutes. This rapid onset ensures swift relief from infestation.
When does the action of flea drops begin? - in detail
The effect of topical flea treatments starts shortly after the product is applied to the animal’s skin. Most modern formulations deliver a rapid kill within 30 minutes to 2 hours for adult fleas that contact the treated surface. The precise onset depends on the active ingredient:
- Fipronil‑based drops: fleas begin to die within 30 minutes; full efficacy reached in 4 hours.
- Imidacloprid‑containing products: adult fleas are immobilized in 1–2 hours; mortality is complete by 4 hours.
- Selamectin solutions: fleas start to be affected within 1 hour; complete kill occurs by 6 hours.
Several variables influence the timing:
- Application site – proper spreading over the back and neck ensures optimal distribution through the skin’s lipid layer.
- Hair length and density – dense or long coats may delay absorption, extending the onset by up to an additional hour.
- Ambient temperature – temperatures above 20 °C accelerate absorption; colder conditions can reduce the speed of action.
- Pet weight – larger animals receive a higher dose, which generally maintains the same onset but may require a longer period for full coverage.
After the initial kill, the product continues to inhibit development of flea eggs and larvae. Egg hatch suppression begins within 24 hours, and the life‑cycle interruption persists for the duration of the product’s label‑specified protection period, typically 30 days. Re‑application before the end of this interval restores the rapid adult‑kill phase.