I am speculating (with some evidence) you should be able to use vampiric grip on werewolves. You however can't use it on anything bigger than a giant.

I have done it quite a few times on giants but I couldn't throw mammoths,that would be way overpowered but still throwing a mammoth off a mountin would be epic.

Vampiric Grip works like "Fus Ro Dah", in a way... Anything that is immune to "Fus Ro Dah" will be immune to Vampiric Grip... Dragons, Mammoths, Dwarven Spheres, etc.

Ok awesome I just seen my first wild werewolf!!!! I was walking to riften and there it was fighting a group a vampires so I let it play out the vamps won then I took them out fireball style it was epic.

I saw mine in Riften as well, and also the Vampire won. Havent seen one since then, im going to start walking around only at night and deep in the woods to increase my chances.