How do drops work on fleas? - briefly
Topical insecticide drops penetrate the flea’s exoskeleton, delivering neurotoxic agents that disrupt nerve transmission and cause rapid immobilization and death. The formulation spreads over the host’s skin, maintaining continuous exposure as fleas move across the treated area.
How do drops work on fleas? - in detail
Topical flea treatments are liquid formulations applied directly to the animal’s skin, typically at the base of the neck. The solution spreads across the skin surface, forming a thin film that remains in contact with the epidermis and sebaceous glands.
After application, the active substances penetrate the outermost skin layer within minutes. Absorption occurs through the stratum corneum and enters the lipid‑rich sebaceous glands, where they are released slowly into the surrounding tissue and hair follicles. This creates a reservoir that maintains a constant concentration of the insecticide on the skin and in the coat.
The insecticidal component belongs to one of several pharmacological classes:
- Neonicotinoids – bind to nicotinic acetylcholine receptors, causing paralysis and death of adult fleas.
- Insect growth regulators (IGRs) – mimic juvenile hormone, preventing maturation of eggs and larvae.
- Spinosads – disrupt neuronal transmission by targeting nicotinic acetylcholine receptors and GABA‑gated chloride channels.
- Pyrethrins/pyrethroids – modify sodium channel function, leading to rapid knock‑down of crawling stages.
These agents act on different flea life stages. Adult insects contacting the treated coat ingest or absorb the compound, resulting in mortality within 4–8 hours. Eggs laid on the animal are exposed to IGRs, which inhibit hatching. Larvae present in the environment receive residual exposure when the animal’s fur sheds contaminated particles, extending control for up to several weeks.
Safety profile depends on species, body weight, and health status. Dogs tolerate most neonicotinoids and spinosads at labeled doses; cats are sensitive to pyrethrins and require formulations free of these agents. Proper dosage calculation prevents systemic toxicity. Resistance monitoring shows that rotating active ingredients reduces the likelihood of flea populations developing tolerance.
Correct usage of «flea drops» involves applying the exact amount specified for the animal’s weight, ensuring the skin is dry, and preventing licking until the product dries. Regular re‑application according to label intervals sustains efficacy throughout the flea season.