How do flea and tick drops work? - briefly
Flea and tick spot‑on treatments contain insecticidal agents that spread across the skin, forming a protective layer in the animal’s oil and sebaceous secretions; the chemicals are absorbed into the bloodstream, killing parasites on contact and preventing new infestations. Effectiveness depends on rapid systemic distribution, which eliminates adult insects and disrupts their life cycle.
How do flea and tick drops work? - in detail
Topical flea‑ and tick‑control products contain one or more active ingredients that migrate from the application site into the animal’s systemic circulation. After the drop is placed on a thin area of skin, the formulation spreads across the coat, penetrates the epidermis, and enters the bloodstream. Once in the blood, the compound reaches the sebaceous glands, where it is secreted onto the skin surface and into the oily layer that coats hairs. This distribution creates a continuous protective barrier that contacts parasites during feeding.
The antiparasitic effect relies on distinct biochemical actions:
- Neurotoxic agents (e.g., fipronil, imidacloprid) bind to ligand‑gated ion channels in the nervous system of insects and arachnids, causing uncontrolled neuronal firing and rapid death.
- Insect‑growth regulators (e.g., pyriproxyfen) mimic juvenile hormone, disrupting metamorphosis and preventing development of eggs and larvae.
- Acaricidal compounds (e.g., selamectin) interfere with neurotransmission in ticks, leading to paralysis and cessation of feeding.
Efficacy persists for weeks because the active substance remains in the lipid layer and is slowly released. The duration depends on factors such as animal size, coat thickness, bathing frequency, and environmental temperature. Typical product labels guarantee protection for 30 days under normal conditions.
Safety considerations include:
- Minimum weight thresholds to ensure adequate dosage.
- Avoidance of application to irritated or broken skin.
- Observation for adverse reactions such as localized erythema or gastrointestinal upset.
- Awareness of potential resistance development in parasite populations, which may necessitate rotation of active ingredients.
Correct use involves applying the prescribed number of drops directly to the skin, spreading the liquid over the dorsal surface, and preventing the animal from licking the area until the solution dries. Adherence to these steps maximizes absorption, sustains antiparasitic activity, and minimizes risk to the host.