GZ-793A is a selective inhibitor of vesicular monoamine transporter 2 (VMAT2), which transports the monoamine neurotransmitters from cellular cytosol into synaptic vesicles. GZ-793A is 50-fold selective for VMAT over the serotonin or dopamine transporters. VMAT2 has recently been considered a target for the treatment of methamphetamine abuse. In rat studies, GZ-793A decreased self-administration of methamphetamine with no development of tolerance.