Nefopam is a modestly potent but non-selective inhibitor of serotonin and noradrenaline reuptake (S+NRI).In addition the mol. possesses significant central antihistamine (H1 antagonist) activity.Nefopam (1) suffers from extensive first pass metabolism to an inactive N-demethyl metabolite, lowering bioavailability and limiting efficacy in animal models.The discovery of novel anti-emetic pharmacol. in nefopam (1) has led Arakis to undertake a property driven medicinal chem. program aimed at improving the potency and selectivity of the template while enhancing pharmacokinetics.ARAK0029 (2) is a potent selective serotonin reuptake inhibitor (SSRI), devoid of antihistamine activity.The compound is primarily metabolized by O-demethylation to an -active′ metabolite increasing the pharmacodynamics of the template.A second series based on ARAK0051 (3) are representative of a potent class of S+NRI′s.Strategies to improve pharmacokinetics and eliminate CYP2D6 activity will be presented and exemplified by derivatives from a second wave of medicinal chem.Lead compounds are now devoid of both H1 antagonist activity and the CYP2D6 inhibition present in the parent mol.