How do flea drops for dogs work? - briefly
The liquid is applied to the skin at the back of the neck, spreads across the coat, and is absorbed into the bloodstream, where systemic insecticides disrupt the nervous system of fleas that bite, causing rapid death. This protection lasts several weeks, preventing new infestations.
How do flea drops for dogs work? - in detail
Flea spot‑on products are liquid formulations applied directly to a dog’s skin, usually between the shoulder blades. The active ingredient is absorbed through the skin into the bloodstream and distributed via the animal’s circulatory system. When a flea bites, it ingests the compound, which interferes with the parasite’s nervous system, leading to paralysis and death within hours.
The process involves several steps:
- Application: A calibrated drop is placed onto a shaved or hair‑free area to ensure direct contact with the skin.
- Absorption: Lipophilic ingredients penetrate the epidermis and enter the capillary network. The formulation often contains a solvent (e.g., ethanol) that speeds permeation.
- Distribution: Once in the bloodstream, the chemical circulates to all body tissues, reaching fleas wherever they attach—on the coat, ears, or paws.
- Mode of action: Most spot‑on agents belong to one of three classes:
- Neurotoxic insecticides (e.g., fipronil, imidacloprid) that block GABA‑gated chloride channels, causing uncontrolled neuronal firing.
- Insect growth regulators (e.g., methoprene) that mimic juvenile hormone, preventing larvae from maturing.
- Combination formulas that pair a neurotoxin with a growth regulator for both adult kill and interruption of the life cycle.
- Efficacy duration: The concentration of active ingredient remains lethal to fleas for a period ranging from four weeks to several months, depending on the product’s formulation and the dog’s metabolism.
Safety considerations include:
- Using only products labeled for canine use; some ingredients are toxic to cats.
- Avoiding application on broken skin or near the eyes and mouth.
- Observing the recommended dosage based on the dog’s weight to prevent overdose.
Overall, spot‑on treatments provide systemic protection by delivering a dose of insecticidal or growth‑regulating chemicals that travel through the dog’s body, ensuring that any flea that feeds on the host is quickly incapacitated, thereby breaking the infestation cycle.