I loved those little dexedrine xr's, I never felt the need to crush them, I would just take a couple at a time and enjoy the hell out of the lift they gave me. I wish I still had access to those sometimes, I still get the instant release ones and they are great too, a little too great. Be careful if you have a bunch, it's easy to get carried away. I hope you have some benzos or something to come down with.
If you're new to amphetamines I wouldn't take more than ten to twenty milligrams your first time, I'm experienced and have a tolerance to rx amps and Fifty milligrams at once would be way too much for me. I'm a lightweight though. Still, if you're new to them go slow, dex can fool you because you'll think that you're just getting a relaxing amp high then all of a sudden your heart will be beating a million miles a minute and you'll be inclined to call 911...
So, take it slow, everyone reacts differently, people can tell you their experiences but they hit everyone a little differently.