you can give the whole pill, any extra the kitty will pee out. It may be easier to melt it in some water and add that to the food. I used capsules, so it was easy to empty and mix into wet food.
I usually crush two tabs and add into a split breakfast and again in dinner for Shadoe and Oliver.
It's a little less than recommended for their sizes - 17lb and 31lb - but it's helpful for them.