If you have an air hammer or press, those studs will come right out with no damage. Using a regular hammer will swag and gall the ends. If you have put enough miles on the rig to wear out a drum, you may as well put in new studs for under $15 a side. Make sure they are fully seated though, and be sure to take an old one in order to get the right ones.
Also, if you were unlucky enough to run a brake pad down to the steel and you have LOTS of little metal flakes on your backing plates, you probably should replace your outer axle seal. I have seen them leak after this on nearly every rig after 5-10k miles.