Differences in tolerability or efficacy may be attributable to age-related physiological changes in the pharmacokinetics of drugs, particularly regarding drug metabolism (Skinner et al., 2003; Turnheim, 2003).Duloxetine hydrochloride (DLX) is a selective serotonin (5-HT) and norepinephrine reuptake inhibi-tor (SNRI) that has comparable affinities for both 5-HT and norepinephrine transporters (Bymaster et al., 2001), but negligible affinity for other neuronal recep-tors (Volonteri et al., 2010; Ball et al., 2013).The pharmacokinetic characteristics of duloxetine include hepatic oxidation and conjugation via cytochrome P450 (CYP) 2D6 and CYP1A2 (Skinner et al., 2003), a plasma elimination half-life of 12 h, and steady-state concentrations that are attained within three days from a fixed dose regimen start. The time to reach the maximum concentration (T max) is 6 h (Sharma et al., 2000; Volonteri et al., 2010). In elderly, pharmacokinetic analyses suggest that the typical values for clearance decrease by ap-proximately 1% for each year of age between 25 to 75 years of age.