<unk>  is a Sympathomimetic that is FDA approved for the treatment of neurogenic orthostatic hypotension. There is a Black Box Warning for this drug as shown here.  Common adverse reactions include Headache, dizziness, nausea, hypertension, and fatigue.
Droxidopa
Diphenidol
Carbidopa
Levodopa
Trifluperidol
Melevodopa
Penfluridol
Benperidol