How do flea and deworming drops work for cats? - briefly
Flea‑control drops contain insecticidal chemicals that disperse across the skin and fur, killing adult fleas and interrupting their life cycle. Deworming drops provide systemic anthelmintic agents that are absorbed into the bloodstream to eradicate common intestinal parasites such as roundworms and hookworms.
How do flea and deworming drops work for cats? - in detail
Flea and deworming spot‑on products are applied to the skin at the base of a cat’s skull. The liquid spreads over the fur and is absorbed through the sebaceous glands, entering the bloodstream and reaching peripheral tissues.
Flea control mechanism
- Active compounds such as imidacloprid, selamectin, fipronil, or nitenpyram bind to insect‑specific glutamate‑gated chloride channels or nicotinic acetylcholine receptors.
- Binding forces the channel to stay open, causing uncontrolled chloride influx or acetylcholine overstimulation. The result is rapid paralysis and death of adult fleas that contact the treated surface.
- Systemic distribution provides a “kill‑on‑contact” effect for newly hopping fleas that bite the animal, interrupting the life cycle before eggs are laid.
- Some ingredients (e.g., pyriproxyfen) act as insect growth regulators, preventing development of eggs and larvae in the environment.
Deworming mechanism
- Ingredients such as pyrantel pamoate, milbemycin oxime, praziquantel, or fenbendazole are absorbed through the skin, then travel via the circulatory system to the gastrointestinal tract where parasites reside.
- Pyrantel mimics acetylcholine, binding to nematode nicotinic receptors, causing spastic paralysis and expulsion.
- Milbemycin and ivermectin open glutamate‑gated chloride channels in nematodes and cestodes, leading to flaccid paralysis and death.
- Praziquantel increases calcium permeability in tapeworm teguments, inducing severe spasms and disintegration.
- The drugs are poorly metabolized by the cat, allowing sufficient concentrations to remain in the gut lumen for several days, providing a broad‑spectrum protective window.
Pharmacokinetic considerations
- Peak plasma levels are reached within 2–4 hours after application; effective concentrations persist for 1–4 weeks depending on the active ingredient.
- Lipophilic molecules distribute into fatty tissue, extending the duration of action and enabling contact kill for ectoparasites.
- Renal and hepatic elimination is minimal for most spot‑on agents, reducing the risk of systemic toxicity when used at the label‑specified dose.
Practical aspects
- Apply the exact dose recommended for the cat’s weight to a shaved area of skin to prevent dilution by fur.
- Do not bathe or wet the cat for at least 24 hours after treatment; this ensures complete absorption.
- Repeat the application according to the product’s interval (typically monthly) to maintain continuous protection against both external and internal parasites.
The combined action of neurotoxic insecticides and antiparasitic chemotherapeutics delivers rapid kill of fleas on contact and systematic eradication of intestinal worms, safeguarding the cat’s health with a single topical administration.