Paroxetine is a benzodioxole containing a piperidine ring substituted with (1,3-benzodioxol-5-yloxy)methyl at position 3 and 4-fluorophenyl at position 4, forming the (3S,4R)-diastereomer. It is a highly potent and selective 5-HT uptake inhibitor with a Ki value of 0.05 nM for serotonin transporter binding. Ki values for [3H]-5-HT, [3H]-l-NA, and [3H]-DA uptake inhibition are 1.1, 350, and 1100 nM, respectively. It shows minimal affinity for alpha1-, alpha2-, beta-adrenoceptors, 5-HT2A, 5-HT1A, D2, and H1 receptors at concentrations below 1000 nM, but exhibits weak affinity for muscarinic ACh receptors (Ki = 42 nM). It functions as an antidepressant, anxiolytic, serotonin uptake inhibitor, hepatotoxic agent, and P450 inhibitor. It belongs to piperidines, benzodioxoles, organofluorine compounds, and aromatic ethers, and is functionally related to monofluorobenzene. It is the conjugate base of paroxetinium(1+).
