Pyrantel pamoate is an dewormer commonly available over the counter. The brands vary, Rid Worm is one, so you'll need to look for pyrantel pamoate listed as the active ingredient. It can come in paste and liquid form, and the dose will depend on the size and age of your dog. It's also listed on the packaging.
Be sure the product you purchase has the correct ingredient. The other commonly available dewormer is piperazine and it is primarily effective against round worms. The pyrantel is more "broad spectrum" and will work against both types of parasites.