I'm taking them as part of chemotherapy. Don't know what kind or how much, but they do increase my appetite. I told my doctor and he cut back on the amount, thank goodness and I can tell that I'm not as hungry as I was.
But I've heard that long term use can cause bone damage so be careful.
If your doctor gave them to you, though, he or she is assuming that the benefits will outweigh any negative side effects.