Need an expert (pharmacist?) who can testify to the synergistic effect of mixing booze with prescription meds (vicodin and effexor) in my DWI trial. Any suggestions? I'm in the Houston area.

You could probably get by with a pharmacist, but I would recommend a forensic toxicologist. As the name would imply, forensic toxicologists are very familiar with these issues as well as the requirements of the courts.

You might check with the lab that performed the tests, especially if it is a government entity. If not, I'm sure there are some consulting forensic toxicologists in your area.