How long do flea drops remain effective for cats? - briefly
Flea spot‑on treatments generally protect cats for roughly one month after a single application. Certain newer formulations extend coverage to 8–12 weeks, but the standard label claim remains about 30 days.
How long do flea drops remain effective for cats? - in detail
Flea spot‑on treatments for felines work by dispersing an insecticide across the skin surface, where it spreads through the lipid layer of the coat and enters the bloodstream. The chemical remains active until it degrades or is removed by external factors, providing protection against adult fleas, larvae, and, in some formulations, ticks and mites.
Key variables that alter the period of protection include:
- Body weight: dosage is calibrated to specific weight ranges; under‑dosing shortens efficacy.
- Coat characteristics: dense or long fur can impede distribution, reducing contact time.
- Grooming habits: excessive licking may remove product from the skin.
- Water exposure: bathing, swimming, or heavy rain can wash away the active ingredient.
- Ambient temperature and humidity: high heat accelerates degradation; low humidity slows it.
- Parasite resistance: populations with reduced susceptibility may survive shorter exposure periods.
Typical duration for the most common active ingredients:
- Imidacloprid + pyriproxyfen – 4 weeks
- Fipronil – 4 weeks
- Selamectin – 4 weeks
- Fluralaner (long‑acting) – up to 12 weeks
- Afoxolaner – 8 weeks
- Nitenpyram (oral, not spot‑on) – 24 hours (included for comparison)
These intervals assume correct application to a healthy cat, adherence to the weight‑specific dosing chart, and avoidance of excessive water contact.
To maintain continuous protection, reapply the product according to the manufacturer’s schedule, typically monthly for short‑acting formulations and every 8–12 weeks for long‑acting options. Verify that the cat’s weight remains within the recommended range; adjust dosage if the animal gains or loses significant mass. Conduct regular flea counts on the coat and in the environment; increase treatment frequency if infestations persist. Consult a veterinarian when switching brands or when the cat has skin conditions, renal disease, or is receiving concurrent medications, as interactions may affect efficacy.