<unk>  is a central alpha-2 adrenergic agonist that is FDA approved for the treatment of hypertension.   Common adverse reactions include orthostatic hypotension, abdominal pain, constipation, xerostomia, dizziness, headache, insomnia, somnolence, impotence, fatigue.
Guanfacine
Nabilone
Atomoxetine
Naltrexone 
Vilazodone
Nortriptyline
Dapoxetine
Duloxetine