I would tell you not to do it, but you didn't come here to listen to real advice.
You just wanted permission to do something that you know is risky.
Serotonin Syndrome is far more serious than you could possibly imagine, a fate to be avoided at all costs!
And yes there are case studies of people taking DXM and MDMA in close proximity and suffering SS.
To minimize risk here is what you must do:
Exercise right now.
It will speed your metabolism which clears the body of DXM metabolites.
It will increase the plasticity of your existing serotonin axons through the release of BDNF.
If you begin to experience a negative reaction, even a mild one, lower your body temperature quickly.
Although hypothermia is a sign of advanced SS, any chest pain, abdominal pain, or anxiety could be early signs.
Lowering core body temperature is the first line of defense because it directly modulates toxicity to serotonin nerves.
In a hospital setting the very first treatment is removal of clothing and application of cold wet towels to the face, chest, neck, and back.
This is your most powerful control over a truly frightening and possibly fatal reaction.
Keep in mind that acute reactions to MDMA have occurred several days AFTER rolling.
So keep an eye out for any of these symptoms for a few days.
And STOP taking DXM.
Also, sipping an electrolyte like gatorade will support your kidneys ability to remove water from the bloodstream.
Saline IV is the second supportive care given to a patient in an ER because it is a defense against hyponatremia.
The leading cause of hyponatremia isn't 'water intoxication' it is SIADH, or syndrome of inappropriate anti-diuretic hormone.
And MDMA always induces a release of ADH, while acute reactions often involve much higher levels.
I'm certain I experienced hyponatremia without any fluid intake three days AFTER my last MDMA exposure.
It puts pressure against the brain, by the way, making it the leading cause of death among MDMA users.
Although water is often blamed, there are confirmed cases of hyponatremia that did not involve excessive fluid intake.
So make yourself cold and drink salty fluid.
There is only one more tool - benzodiazapenes.
A valium or xanax can relax the smooth muscle tissue that becomes tense and erratic during SS.
This fights the hypothermic response and it lowers toxic glutamate in the brain.
It will also fight the breakdown of skeletal muscle, which can cause fatal kidney damage due to the release of myoglobin!
So these three things play a very important role in influencing a toxic cascade of events.
Memorize them, write them down, and tell your friends.
Cold, electrolytes, and benzos.
Do not intake high levels of salt as this can cause a fatal infarct in the brainstem - only slow intake of diluted electrolytes.
Of course if you really fear for your life, it is wise to contact medical help immediately.
But it helps to know exactly what they are going to do to you - and do them first.
The only medical tool they have beyond this is dantrolene, a serotonin antagonist, which must be administered very carefully.
When this doesn't work you normally hear about the rare event of death from MDMA use.
But you should be more concerned about neurotoxicity anyways.
MDMA will cause 'brain damage' and your dosage is really the greatest control.
That means that taking more than one dose is VERY foolish tonight.
Each subsequent dose increases neurotoxic damage.
Dosage is more important than any of the 'supportive care' options I listed above.
The best choice would be to wait at least two weeks after DXM to do MDMA.
And by the way, DXM is a dirty retarded drug that has been surpassed and replaced by ketamine.
There is no reason to use such a stupid drug when others exist, so just stop robo-tripping.
I hope all goes well for you tonight.
Make sure the AC is running...