H'm. Wonder how you would get a garlic pearl in a cat?
If you want to know just google "How to give a cat a tablet", and for your keyboards sake don't have a drink whilst you read it
I've always found Mandy at Swift As A Bird (644 0554) to be good for things like this, she has quite a range of different flea treatments not just the one size fits all you might find elsewhere.
If you have no luck with other suggestions you might want to give her a call.