How long do Bars drops for ticks and fleas act on dogs? - briefly
A single application protects the dog for approximately four weeks. After that period efficacy wanes and re‑application is necessary.
How long do Bars drops for ticks and fleas act on dogs? - in detail
Bars topical solution provides continuous protection against ticks and fleas for a period of approximately one month after each application. The product contains fipronil and (S)-methoprene, which remain active on the skin and coat, killing parasites that contact the treated area for up to 30 days.
Efficacy depends on several variables:
- Weight class – the dose is calibrated for dogs weighing 4 lb (1.8 kg) to 140 lb (63.5 kg); under‑dosing in larger dogs shortens the protection window, while overdosing does not extend it.
- Bathing and swimming – water exposure does not significantly reduce activity, but excessive shampooing within the first 24 hours can lower the concentration on the skin.
- Environmental pressure – high tick or flea infestations may increase the chance of re‑infestation shortly before the 30‑day mark, prompting earlier reapplication.
- Health status – compromised skin barrier or severe dermatitis can impair absorption, potentially reducing the effective duration.
Reapplication should occur at 30‑day intervals to maintain uninterrupted coverage. If a dog is exposed to a heavy parasite load, a supplemental treatment may be considered, but it must not exceed the label‑specified frequency.
Safety data indicate that the active ingredients persist in the skin without systemic accumulation, allowing daily contact with humans and other pets without adverse effects when used as directed.