I have a mini-Schnauzer who is 7 and luckily, have had only one flea infestation but for anyone who has had a similar experience, even one can be a nightmare. He was on Advantix when I noticed him scratching, something he rarely does. Sure enough, I later discovered he had fleas, lots of them. My house had fleas, lots of them - everywhere. I applied more Advantix but it did not kill them, I treated him with flea shampoo and that killed the fleas on him momentarily until the ones already in my house jumped back on him and infested him again. I spent literally hundreds of dollars on flea sprays for the house with growth inhibitors and Fipronil insecticide but the fleas always came back. I had my carpets treated and steam cleaned to kill the eggs but they miraculously survived and I again found fleas throughout my house. In desperation, I called my vet and he recommended Comfortis, an oral medication that is a neurotoxin for certain invertebrates such as fleas with minimal adverse reaction for my poor infested pooch who by this time had bare patches of skin where he had scratched away his fur. The vet told me that the fleas will begin to die within 15 minutes of administering the drug and sure enough that is exactly what happened. Fleas started to fall off my canine friend dying within minutes and within a few days, I could find none on my dog and within a week, none in my house either. Whenever a flea somewhere in my house sensed the dog and jumped on for a meal, the first bite killed it within minutes and that is how the infestation in my house was finally eliminated - one flea at a time.
Unlike all the other products, Comfortis kills any flea within minutes after it bites the dog once. Growth inhibitors prevent the female flea from producing viable offspring but she she and all her friends survive for weeks biting the poor animal every time they are hungry and biting you if they fell off your dog and discovered that you're almost as tasty as Fido.
Remember to always give the medication with food as this decreases adverse reactions. Fortunately, my dog has had no real problems taking this drug and at worse, seems a bit lethargic for a few hours after he gets it with his food. I read some horror stories online about Comfortis but my pet has done fine with it. Speak to your vet to make sure your pet is healthy enough to take this medication. My vet told me that he is unaware of any significant problems resulting from this medication and he has recommended it to thousands of pet owners. The worse he has seen is vomiting soon after giving the dog the pill and usually, the owner didn't feed the dog as recommended by the manufacturer.