Hi,
I think there might be a little confusion (well it could just be my confusion lol), depression isn't the only issue associated with fatigue. So i surmise that if your fatigue is caused by a medical condition, for instance MS, thyroid, hormonal imbalance, autonomic dysfunction, hypoglycemia, diabetes, chronic pain etc. then drugs that target emotion are likely to not be on much help, if the fatigue you've got is not due to depression.