Enantiomeric (dl)-threo-Ethylphenidate is a potent psychostimulant that acts as both a dopamine reuptake inhibitor and norepinephrine reuptake inhibitor, meaning it effectively boosts the levels of the norepinephrine and dopamine neaurotransmitters in the brain, by binding to, and partially blocking the transporter proteins that normally remove those monoamines from the synaptic cleft. It is formed when ethanol and methylphenidate are coingested, via hepatic transesterification. Ethylphenidate formation appears to be more common when large quantities of methylphenidate and alcohol are consumed at the same time, such as in abuse or overdose scenarios. This carboxylesterase-dependent transesterification process is also known to occur when cocaine and alcohol are consumed together, forming cocaethylene.
Ethylphenidate is more selective to the dopamine transporter (DAT) than methylphenidate, having approximately the same efficacy as the parent compound, but has significantly less activity on the norepinephrine transporter (NET). It has nearly a identical dopaminergic pharmacodynamic profile as methylphenidate, possessing appreciable affinity for the inhibitory G protein-coupled dopamine subtype-2 receptors in the striatum and mesolimbic regions of the brain, including the nucleus accumbens, which is primarily responsible for its pro-euphorant and reinforcing effects.