Desmethylsertraline (DMS), also known as norsertraline, is an active metabolite of the antidepressantdrugsertraline. Like sertraline, desmethylsertraline acts as a monoamine reuptake inhibitor, and may be responsible for some of its parent's therapeutic benefits; however, the effects of DMS's main activity of increasing serotonin levels via binding to the serotonin transporter appears to be negligible as in vivo testing showed no measurable change in brain activity despite a nearly 20-fold increase in DMS blood levels compared to the EC50 (i.e. the amount required to achieve the desired effect in 50% of the population) of its parent drug sertraline.[1] DMS is significantly less potent relative to sertraline as a serotonin reuptake inhibitor (Ki = 76 nM vs. 3 nM, respectively), but conversely, is more balanced as a monoamine reuptake inhibitor (5-HT (Ki) = 76 nM; NE (Ki) = 420 nM; DA (Ki) = 440 nM), which has the effective result of DMS contrarily behaving as a serotonin-norepinephrine-dopamine reuptake inhibitor (SNDRI), with about 5.5-fold preference for inhibiting serotoninreuptake relative to catecholamine reuptake.[2]
^Wong DT, Bymaster FP, Engleman EA (1995). "Prozac (fluoxetine, Lilly 110140), the first selective serotonin uptake inhibitor and an antidepressant drug: twenty years since its first publication". Life Sciences. 57 (5): 411–441. doi:10.1016/0024-3205(95)00209-o. PMID7623609.
