Furthermore, DXM is contraindicated with MDMA. It is a both a serotonin releaser and a reuptake inhibitor, as well as being metabolized by the same liver enzyme as MDMA, thus preventing the proper breakdown of MDMA. Furthermore, DXM inhibits perspiration, elevating body temperature. Combining DXM and MDMA, therefore, significantly increases ones chance of "serotonin syndrome," a rare but potentially fatal condition. We witnessed a number of serotonin syndrome occurrences involving accidental DXM/MDMA combinations, and there are a number of documented cases of serotonin syndrome resulting from people who had taken DXM-containing cough syrup while on MAOIs or SSRIs, two types of serotonin-affecting anti-depressants.
Report from DanceSafe January 2001