<p>The efficacy of Paroxetine is presumed to be linked to potentiation of serotonergic activity in the central nervous system resulting from inhibition of neuronal reuptake of serotonin (5-hydroxy-tryptamine, 5 HT). Studies at clinically relevant doses in humans have demonstrated that paroxetine blocks the uptake of serotonin into human platelets. In vitro studies in animals also suggest that paroxetine is a potent and highly selective inhibitor of neuronal serotonin reuptake and has only very weak effects on norepinephrine and dopamine neuronal reuptake. In vitro radioligand binding studies indicate that paroxetine has little affinity for muscarinic, alpha1, alpha2, beta adrenergic, dopamine (D2), 5-HT1, 5 HT2 and histamine (H1)-receptors; antagonism of muscarinic, histaminergic and alpha1-adrenergic receptors has been associated with various anticholinergic, sedative and cardiovascular effects for other psychotropic drugs. Because the relative potencies of paroxetine&rsquo;s major metabolites are at most 1/50 of the parent compound, they are essentially inactive.</p>