How do flea drops applied to the nape work? - briefly
When applied to the nape, the liquid spreads across the skin, is absorbed into the bloodstream, and kills fleas that bite the animal. The active ingredient circulates through the animal’s oil glands, delivering protection for several weeks.
How do flea drops applied to the nape work? - in detail
Flea spot‑on products are formulated as liquid solutions containing insecticidal agents that penetrate the skin when applied to the area at the base of the skull. The thin skin in this region allows rapid absorption into the dermal capillary network, after which the active compound enters the systemic circulation and is distributed throughout the animal’s body via the bloodstream. Fleas feeding on the host ingest the compound, which interferes with essential neural pathways, leading to paralysis and death.
Key insecticidal classes and their modes of action:
- Imidacloprid – binds to nicotinic acetylcholine receptors, causing continuous nerve stimulation and fatal convulsions.
- Fipronil – blocks γ‑aminobutyric acid‑gated chloride channels, disrupting inhibitory neurotransmission and resulting in uncontrolled neuronal activity.
- Selamectin – enhances the release of inhibitory neurotransmitters by binding to glutamate‑gated chloride channels, producing paralysis of ectoparasites.
Pharmacokinetic profile:
- Absorption begins within minutes; peak plasma concentrations are typically reached within 2–4 hours.
- Distribution is rapid, reaching skin, hair follicles, and sebaceous glands where fleas reside.
- Elimination half‑life ranges from 7 to 14 days, providing continuous protection for up to one month depending on the formulation.
Application protocol:
- Ensure the coat is dry and free of debris at the nape.
- Part the hair to expose the skin.
- Dispense the exact number of drops specified on the product label onto the exposed skin.
- Allow the solution to dry completely before the animal contacts water or other animals.
Safety considerations:
- Do not apply to animals with known hypersensitivity to the active ingredient.
- Avoid contact with eyes, mouth, and open wounds.
- Keep the product out of reach of children and other pets; accidental ingestion may cause systemic toxicity.
When applied correctly, the systemic distribution of the insecticide eliminates fleas that bite the host and interrupts the life cycle by preventing the development of eggs and larvae in the environment.