When do fleas leave after drops? - briefly
Fleas usually detach within 24–48 hours after a correct topical treatment, often beginning to drop off within a few hours as the medication acts. If the infestation persists beyond two days, a repeat application or veterinary consultation is advised.
When do fleas leave after drops? - in detail
Fleas typically disappear from a pet within a predictable period after the application of topical insecticide drops. The active ingredients begin to spread across the skin and coat within minutes, reaching the bloodstream and creating a hostile environment for the parasites. The following timeline summarizes the process:
- First 12–24 hours: Adult fleas start to die as the chemical concentration on the skin reaches lethal levels. Some may still be observed moving, but mortality is high.
- 24–48 hours: The majority of adult fleas are eliminated. Eggs and larvae present on the animal’s fur begin to die or are unable to develop because the adult population that would normally lay new eggs is gone.
- 48–72 hours: Residual activity continues to affect newly hatched fleas that emerge from any remaining eggs on the host. At this stage, most visible signs of infestation have ceased.
- 72 hours to 1 week: The product’s residual effect maintains protection, preventing re‑infestation from stray fleas that may contact the animal. Complete cessation of flea activity is usually confirmed within this window.
Factors influencing the exact duration include the pet’s size, coat thickness, ambient temperature, and the specific formulation used (e.g., fipronil, imidacloprid, or selamectin). Warmer conditions accelerate absorption, while dense or oily coats may delay distribution. Proper application—directly onto the skin at the base of the neck—ensures optimal spread and minimizes gaps in coverage.
If live fleas are still observed after 48 hours, verify that the product was applied correctly and consider environmental control measures such as vacuuming and washing bedding. Persistent infestation beyond one week may indicate resistance, incorrect dosage, or an external source of re‑infestation, warranting veterinary consultation.