I'm getting conflicting results. Phetermine (Fastin) is usually prescribed for weight loss. Weight loss pills can (usually) lead to greater depression in patients with depression. Wellbutrin is also prescribed to patients who are quiting smoking. One of the "side effects" may be a depression of the appetite. But usually is prescribed as an antidepressant. So here is my thinking. If you are on Fastin (Phetermine) for weight loss and got depressed, then instead of taking the wellbutrin to treat the depression, stop taking the fastin and see if your depression "clears up" on its own. OR, if you were depressed to begin with, stop taking the fastin and try the wellbutrin alone and see if that doesn't kill to birds with one stone. I have read that mixing the two can lead to heart palpitations. I would also suggest calling the druggist/pharmacist and see what she/he suggests. Doctors usually do not know all the possible outcomes of mixing medications - that is why it is always strongly suggested you have one pharmacist who deals all your drugs to you. That way s/he will be able to flag a "dangerous" combination and call the Doctor and ask them if they are certain. Medicine has gotten so specialized that there is no way that any one doctor could know the complications and potential outcomes of all of the potential combinations of medications out there. Further with all of these newer medications coming out only pharmacists would be the "first to know" if something is wrong.