How long does Stronghold work on fleas? - briefly
It starts killing fleas within 24 hours of application and maintains efficacy for approximately 30 days.
How long does Stronghold work on fleas? - in detail
Stronghold (imidacloprid) begins killing adult fleas within 30 minutes of topical administration. The product maintains lethal concentrations in the animal’s skin and coat for approximately 30 days, providing continuous protection against new infestations during that period. After the first month, residual activity declines, and a second dose is recommended to sustain efficacy.
Factors that influence the length of protection include:
- Animal size and breed: Larger dogs may retain the drug longer due to greater skin surface area.
- Bathing and grooming: Frequent shampooing can reduce residual levels, shortening the effective period.
- Environmental flea pressure: Heavy infestations may require supplementary control measures in the environment.
Typical dosing schedule:
- Apply the recommended dose once a month.
- Re‑apply after 30 days, or sooner if heavy exposure or excessive bathing occurs.
- Maintain a consistent schedule to prevent gaps in protection.
If a flea bite or infestation is observed before the 30‑day mark, verify correct application and consider environmental treatment, as Stronghold does not eradicate immature stages (eggs, larvae) in the surroundings.