DXM (dextromethorphan, found in cough medicines and used as a recreational substance) is an NMDA antagonist with an additional serotonergic component and strong CYP2D6 inhibition.
Risks in combination with MDMA:
- Amplified MDMA effect due to slowed breakdown (CYP2D6 inhibition). Even a “normal” MDMA dose can become an effective overdose.
- Serotonin syndrome risk due to additive serotonergic action
- Hyperthermia amplified — at higher doses DXM has sympathomimetic effects
- Dissociative component distorts the perception of heat, so early warning signs get ignored
In polydrug use (e.g. the “robotripping” context) this combination is common, but pharmacologically risky.
We recommend avoiding this combination. If you use it anyway: low single doses of both substances, clear breaks, and when in doubt only one substance.
Some “cough suppressants” contain DXM — if you have a cold during an MDMA phase, check the labels carefully.