NSDUH is a household survey and as such it probably has quite a bit of error in capturing the real number of drug users. Since most drug consumption is due to addicts, I’m also showing data for those persons that were dependent or abused drugs.
National Drug Threat Assessment 2011 (page 50). The southwest region corresponds to the the US-Mexico border crossings and nearby counties. Basically seizures of all drugs along the US-Mexico border have gone up except for cocaine, probably because cocaine consumption has decreased. (Also see this blog post by Alejandro Hope for Mexican drug seizure data)
MDMA (ecstasy) since all the other numbers are so small. Also keep in mind that MDMA from Mexico grew from a very low starting point, though seizures are now about the size of those along the Northern border in 2006.