How long do flea drops act on cats? - briefly
Topical flea spot‑on treatments for cats provide protection for roughly 30 days after a single application. Effectiveness continues until the next monthly dose is administered.
How long do flea drops act on cats? - in detail
Flea spot‑on products for cats are formulated to release insecticide over a defined period after application to the skin at the base of the neck. The active ingredients—commonly imidacloprid, fluralaner, selamectin, or fipronil—diffuse across the skin surface and into the oily layer of the coat, providing continuous protection.
Typical efficacy windows:
- Monthly formulations (e.g., imidacloprid + pyriproxyfen, fipronil + (S)-methoprene): maintain lethal flea levels for approximately 30 days. Laboratory trials show >95 % kill rate throughout the 4‑week interval, with a gradual decline after day 28.
- Quarter‑yearly products (e.g., fluralaner, afoxolaner): sustain activity for up to 12 weeks. Field data indicate >90 % flea mortality up to day 84, after which efficacy tapers and a new dose is required.
- Extended‑release options (e.g., selamectin): provide protection for 30 days against fleas and additional parasites; efficacy remains above 90 % through the final day of the dosing period.
Factors influencing duration:
- Cat’s weight and hair density – heavier or heavily coated animals may retain more product, potentially extending the protective window by a few days.
- Environmental pressure – high flea infestations can accelerate product depletion, shortening the effective period.
- Bathing and swimming – water exposure within the first 24 hours can reduce absorption; after that, occasional bathing does not significantly affect performance.
- Application accuracy – placing the dose directly on the skin, not just on the fur, ensures optimal distribution.
When a dose is missed or the cat exhibits a flea resurgence before the expected end of the interval, re‑application should occur promptly. Overlapping doses is unnecessary and may increase toxicity risk. Always follow the manufacturer’s label regarding minimum re‑treatment intervals and observe for adverse reactions such as skin irritation or excessive grooming.