How do flea tablets for cats work? - briefly
Flea tablets deliver a systemic insecticide that is absorbed into the cat’s blood, so any flea that feeds on the animal ingests the toxin and is killed. The drug is processed by the body and excreted over a period of weeks, maintaining protection throughout that time.
How do flea tablets for cats work? - in detail
Oral flea treatments for felines contain an insecticidal ingredient that is absorbed through the gastrointestinal tract and distributed via the bloodstream. After ingestion, the compound passes from the stomach into the small intestine, where it enters the portal circulation and reaches systemic circulation. Blood‑borne molecules circulate to the skin, hair follicles, and sebaceous glands, providing continuous exposure to any feeding parasite.
When a flea bites the cat, it ingests a small dose of the active substance embedded in the host’s blood. The insecticide interferes with the flea’s nervous system in one of two ways:
- Neurotoxic agents (e.g., nitenpyram, spinosad): bind to nicotinic acetylcholine receptors, causing rapid paralysis and death within minutes.
- Insect growth regulators (e.g., pyriproxyfen, lufenuron): disrupt chitin synthesis, preventing the development of eggs and larvae, thus breaking the life cycle over several days.
The dosage is calibrated to achieve therapeutic plasma concentrations without harming the cat. Pharmacokinetic data show peak blood levels within 1–4 hours, maintaining effective concentrations for 24–48 hours for fast‑acting agents and up to a month for longer‑acting formulations. This window ensures that newly acquired fleas are killed before they can reproduce.
Safety mechanisms include:
- Selective toxicity: compounds target insect-specific receptors or metabolic pathways absent in mammals.
- Low systemic toxicity: the dose is far below the threshold for adverse effects in cats, as confirmed by toxicology studies.
- Metabolic clearance: the liver and kidneys eliminate the drug after the therapeutic period, reducing residual exposure.
In practice, a single tablet administered with food provides protection for the intended duration, eliminating the need for topical re‑application. Regular monthly dosing aligns with the flea life cycle, preventing infestations from re‑establishing.