We have a 3 year old Springer Spaniel. A few days ago he began scratching---with a vengance. He could not sleep--neither could we. I had just put Frontline on him. So I was certain there was something other than fleas that was the problem. We went to the vet on Friday and sure enough the vet found three fleas on him within seconds of beginning his exam. Dr. Blair recommended Comfortis. I told him I had just put Frontline on him. He said that it would not be harmful to go ahead and give Ollie the pill as well. So, I decided to try it since Ollie was so uncomfortable. By the evening, he was still itchy but some better and he slept better. Today---Two days later he is still scratching but not as much. Ollie weighs 60 lbs. and was given the dosage for dogs weighing up to 60 lbs. I was wondering if maybe he should have the dose for dogs that weigh 60-120 lbs. Does anyone know about the proper dosage?