The best feline restraint around is the simple terry towel, used as follows:

Grasp the cat firmly by the handle. Drape a large towel (bath size) over the cat. (A white towel is preferred, since for some reason it looks strange to a cat's eyes -- as if there's a hole cut out of reality, like the Led Zeppelin Presence album cover. You can stop a charging tiger with a white drape.) Wrap the edges around quickly, flipping the cat over on its back in the process, trying for a neat firm package. Ignore pitiful mewing sounds, but speak gently to your victim, in a low stream of consolatory patter while you give it pills, pour in ear mite medicine, etc. Release cat. Tell it you still love it as it tries to teleport to the other end of your apartment.