I had Huey on Comfortis alone and was giving him his heartworm pill, too. I did that for a couple of years, and then there was Trifexis! Cheaper than buying 2 pills and Huey has had absolutely no side effects from the meds. Same two meds he was on, but I used to give them a week apart. Now he gets them together with no adverse eeffects. He doesn't get outside in the grass a lot, but he does occasionally and I have never, ever seen a flea on him in 4 years.
