5-hydroxy-6-methoxy (S)-Duloxetine is a metabolite of (S)-duloxetine . It is formed from (S)-duloxetine via a 5- or 6-hydroxy duloxetine intermediate, which is formed by the cytochrome P450 (CYP) isoforms CYP1A2 and CYP2D6, and a catechol duloxetine intermediate. 5-hydroxy-6-methoxy (S)-Duloxetine binds to the serotonin (5-HT), norepinephrine, and dopamine transporters with Ki values of 266, 920, and 2,814 nM, respectively.

(S)-5-hydroxy-6-methoxy Duloxetine, an active metabolite of the (S)-duloxetine, functions as a serotonin (5-HT) and norepinephrine reuptake inhibitor. Its formation occurs through the cytochrome P450 (CYP) isoforms CYP1A2 and CYP2D6 via a 5- or 6-hydroxy duloxetine intermediate, followed by a catechol duloxetine intermediate. This compound effectively inhibits the serotonin transporter (SERT), norepinephrine transporter (NET), and dopamine transporter (DAT) across lipid membranes, with inhibition constants (Kis) of 266, 920, and 2,814 nM, respectively, for human transporters.