4-Hydroxyatomoxetine is an active metabolite of Atomoxetine. 4-Hydroxyatomoxetine is metabolized by the enzyme cytochrome P450 2D6 (CYP2D6). Atomoxetine hydrochloride is a potent and selective noradrenalin re-uptake inhibitor (Ki values are 5 nM, 77 nM and 1451 nM for inhibition of radioligand binding to human NET, SERT and DAT respectively).