How do flea drops work on a cat? - briefly
Flea drops are topical formulations applied to a thin spot of skin, where they disperse across the oil layer and release an insecticide that interferes with the nervous system of adult fleas and developing larvae. The active ingredients are absorbed into the bloodstream, delivering continuous protection for several weeks.
How do flea drops work on a cat? - in detail
Flea spot‑on products for cats contain insecticidal agents such as fipronil, imidacloprid, selamectin, or nitenpyram. After application to the dorsal neck region, the liquid spreads across the skin surface through the animal’s natural oils. This trans‑epidermal migration creates a uniform protective layer that reaches the entire body within hours.
The active ingredient penetrates the cuticle of adult fleas when they come into contact with the treated skin. It interferes with neurotransmission by blocking GABA‑gated chloride channels (fipronil) or binding to nicotinic acetylcholine receptors (imidacloprid). The resulting hyperexcitation of the nervous system leads to rapid paralysis and death, typically within 30–60 minutes.
Because the chemical remains in the lipid layer, it continues to affect newly emerging fleas for up to a month. Eggs and pupae are not directly killed, but the interruption of the adult feeding cycle prevents the development of the next generation, effectively breaking the infestation cycle.
Key pharmacological characteristics:
- Absorption: limited systemic uptake; most of the dose stays on the skin.
- Distribution: spread via sebum, reaches all body regions, including tail and paws.
- Persistence: half‑life on the skin ranges from 10 to 14 days, providing continuous efficacy.
- Safety margin: selective toxicity to insects; mammalian GABA receptors are less sensitive, reducing risk of adverse effects when used as directed.
Correct usage guidelines:
- Apply the entire dose to a single spot on the back of the neck, avoiding the face and claws.
- Ensure the cat is dry; moisture can dilute the product and impair spreading.
- Do not bathe or rinse the animal for at least 24 hours after treatment.
- Keep the cat indoors for the first few hours to prevent grooming of the application site.
Potential resistance mechanisms include mutations in target receptor sites that reduce binding affinity. Rotating products with different active molecules can mitigate this risk.
Overall, flea spot‑on treatments function by delivering a neurotoxic agent across the cat’s skin, where it kills adult fleas on contact and sustains a protective barrier that suppresses the flea life cycle for weeks.