S selektivnim delovanjem so skladne tudi ugotovitve in vitro študij, ki kažejo, da ima paroksetin, za razliko od tricikličnih antidepresivov, le majhno afiniteto za alfa1, alfa2 in beta adrenoreceptorje, dopaminske (D2), 5- HT1 podobne receptorje, 5- HT2 in histaminske (H1) receptorje.
In accordance with this selective action, in vitro studies have indicated that, in contrast to tricyclic antidepressants, paroxetine has little affinity for alpha1, alpha2 and beta-adrenoceptors, dopamine (D2), 5-HT1 like, 5-HT2 and histamine (H1) receptors.