I just got back from the vet's office, and Sergei got his 3rd round of his first set of shots. I asked the vet about the Drontol, and he said that was the right medication to give. He seemed impressed that I had some of it handy and had gone ahead and given it to Sergei, but he said that is what he was going to prescribe. I told him about my volunteering for the local shelter, and that is what we give our cats there. He said it will kill just about any kind of worm, especially tapeworm and round worms (stomach worms). I also asked if I should be worried about my other cats, and he said no - it's a young cat problem (that just goes to show that our instincts are right, KAK! I think he's just a baby still! Just like your Sky!)...but it wouldn't hurt to keep an eye of them all. He gave me more to give Sergei in 3 weeks, just to make sure they're all gone! Yay! My little orangie is going to be ok!