After the topical application of FRONTLINE Spot On Dog, the product will spread from the site of treatment to cover the entire surface of the animal within 24 hours. After application, absorption of fipronil through the skin is slight.
No known incompatibilities exist for the use of other insecticides or flea control products concurrently with FRONTLINE Spot On Dog.
Bathing or shampooing the animal up to one hour prior to treatment does not affect the efficacy of the product. Bathing/immersion in water within 2 days after application of the product and more frequent bathing than once a week should be avoided, as no study has been performed to investigate how this affects the efficacy of the product. Emollient shampoos can be used prior to treatment, but reduce the duration of protection against fleas to approximately 5 weeks when used weekly after application of the product. [B]Weekly bathing with a 2% chlorhexidine medicated shampoo did not affect efficacy against fleas during a 6 week long study.[/B