Paroxetine HCl, a phenylpiperidine derivative, is a highly potent and selective ST (serotonin transporter/5-HT) uptake inhibitor. It acts by binding to ST (serotonin transporter/SERT) with high affinity (Ki = 05 nM). In vitro paroxetine competitively inhibits the uptake of 5-HT by rat hypothalamic and cortical synaptosomes with only very weak inhibitory effects on SLC6A2 (noradrenaline) uptake and DAT (dopamine) uptake. Paroxetine HCl has also displayed a high affinity for muscarinic acetylcholine receptors. Other experiments have shown Paroxetine HCl to inhibit NOS (nitric oxide synthase) and also to be both a substrate and an inhibitor of CYP2D6 (cytochrome isoenzyme P450 2D6).A highly potent and selective serotonin (5-HT) uptake inhibitor Paroxetine HCl, a phenylpiperidine derivative, is a highly potent and selective ST (serotonin transporter/5-HT) uptake inhibitor. It acts by binding to ST (serotonin transporter/SERT) with high affinity (Ki = 05 nM). In vitro paroxetine competitively inhibits the uptake of 5-HT by rat hypothalamic and cortical synaptosomes with only very weak inhibitory effects on SLC6A2 (noradrenaline) uptake and DAT (dopamine) uptake. Paroxetine HCl has also displayed a high affinity for muscarinic acetylcholine receptors. Other experiments have shown Paroxetine HCl to inhibit NOS (nitric oxide synthase) and also to be both a substrate and an inhibitor of CYP2D6 (cytochrome isoenzyme P450 2D6). A highly potent and selective serotonin (5-HT) uptake inhibitor