Praziquantel, when used correctly, de-worms all pets - fish, cats, dogs, etc. This is my primary de-wormer. Highly efficient and safe. I buy it by a kilo from Fishman chemicals. The obstacle is that it is not water-soluble, so I just suspend in a glass of water and dump it in.
Off-the-shelf prazi products usually employ some sort of non-aqueous solvent to help get it in the water.
Of course, it'd be 100 times more effective if you can soak the cat's food in it or get it in his food the way people give pills to their dogs and then have him eat it.
Good luck mate.