MedicationsDog on Sentinel has fleas. What's the best way to treat and prevent?
You're correct that Sentinel is considered a "passive" flea control product - it doesn't kill adult fleas, just keeps their eggs from being able to hatch. Capstar would be quite effective at killing any fleas that he currently has on him. It shouldn't be necessary to wash bedding, etc. since the Sentinel will ensure that the fleas are not able to reproduce.
In my experience, some dogs do fine with Sentinel as their only flea control method if they are in an environment where they are rarely exposed to fleas. But if you're seeing fleas from time to time, or if your dog has flea allergies or other skin sensitivities, then I would recommend using an adulticide like Nexgard or Bravecto along with his Sentinel.
Updated on September 24th, 2025