Agomelatine hydrochloride (S-20098 hydrochloride) is a specific MT1 and MT2 receptor agonist with Ki values of 0.1 nM for CHO-hMT1, 0.06 nM for HEK-hMT1, 0.12 nM for CHO-hMT2, and 0.27 nM for HEK-hMT2, respectively [1]. Additionally, Agomelatine hydrochloride is a selective antagonist of the 5-HT2C receptor with pKi values of 6.4 and 6.2 for native (porcine) and cloned human 5-HT2C receptors, respectively [2].