The following drugs have DRI action and have been or are used clinically specifically for this property: amineptine, dexmethylphenidate, difemetorex, fencamfamine, lefetamine, levophacetoperane, medifoxamine, mesocarb, methylphenidate, nomifensine, pipradrol, prolintane, and pyrovalerone. The following drugs are or have been used clinically and possess only weak DRI action, which may or may not be clinically-relevant: adrafinil, armodafinil, bupropion, mazindol, modafinil, nefazodone, sertraline, and sibutramine. The following drugs are or have been clinically used but only coincidentally have DRI properties: benzatropine, diphenylpyraline, etybenzatropine, ketamine, nefopam, pethidine (meperidine), and tripelennamine. The following are a selection of some particularly notably abused DRIs: cocaine, ketamine, MDPV, naphyrone, and phencyclidine (PCP). Amphetamines, including amphetamine, methamphetamine, MDMA, cathinone, methcathinone, mephedrone, and methylone, are all DRIs as well, but are distinct in that they also behave, and potentially more potently as dopamine releasing agents (DRAs) (due to Yerkes–Dodson's law, 'more potently stimulated' may not equal more optimally functionally stimulated). There are very distinct differences in the mode of action between dopamine releasers/substrates & dopamine re-uptake inhibitors; the former are functionally entropy-driven ("i.e." relating to hydrophobicity) and the latter are enthalpy-driven ("i.e." relating conformational change). Reuptake inhibitors such as cocaine induce hyperpolarization of cloned human DAT upon oocytes that are naturally found on neurons, whereas releasing agents induce de-polarization of the neuron membrane.