[matese]

I have used Comfortis pills in the past it starts working one hour after taken, that kills adult, baby fleas, larva, eggs, it must be the same as the Sentinel . This past fall I gave my newly adopted 3 y/o a dose of frontline, he came to me with fleas, I went back to the vet to get a package of Frontline as I only had that one dose, the vet gave him a Comfortis pill, she said it was ok to give even tho the day before I applied the Frontline on him, as Comfortis starts working in an hour. Always check with your vet before you do anything regardless the age of the dog. I don't feel using Frontline is needed if she was given Sentinel, if it is like Comfortis it works for 30 days, after 30 days you can use Frontline or a protection of your choice, many members use other products that works best for their area. Your pup is protected, you can take her out, if you have any leaves in your area I suggest not allowing her to walk in any leaves, that's where ticks hang out, not to say ticks are ONLY found in leaves, they are all over. Check with your vet about applying a skin based flea / tick prevention. I try to avoid giving Comfortis, I do ONLY if dog is INFESTED with fleas, I use Frontline all year because of the deer and there are a lot of feral cats that like to hang out under my deck in the winter, they are filled with fleas one of my dogs got fleas in Jan, because her hunting grounds was under the deck (mice & moles yummy yorkie hunting vermin) reason feral cats like it there too. Your pup is very young, always talk to vet before giving her anything.