MDMA

High risk of serotonin syndrome

MAO-B inhibitors can increase the potency and duration of phenethylamines unpredictably. MAO-A inhibitors with MDMA will lead to hypertensive crises.

Tramadol and stimulants both increase the risk of seizures.

This combination can easily lead to hypermanic states

Some of the 5-MeO tryptamines are a bit unpredictable and should be mixed with MDMA with care

The combination of MDMA and alcohol may increase strain on the cardiovascular system and lead to increased alcohol consumption. MDMA may also impair one's ability to recognize their level of drunkenness, leading to increased alcohol consumption and poor decision-making. Alcohol may also increase the risk of dehydration and hyperthermia (increased body temperature) when combined with MDMA.

This combination of stimulants will increase strain on the heart, may cause some physical discomfort, and has the chance to cause cardiovascular issues. The anxiogenic and focusing effects of stimulants can increase the chance of unpleasant thought loops and make the experience more uncomfortable, this combination raises these chances. Amphetamines will increase the neurotoxic effects of MDMA, in addition to causing further concerns of hyperthermia due to the inherent nature of the combination. It will also raise one's body temperature, also likely making the combination more neurotoxic.

Caffiene is not really necessary with MDMA and increases any neurotoxic effects from MDMA

Cocaine blocks some of the desirable effects of MDMA while increasing the risk of heart attack.

The combined stimulating effects of the two can be uncomfortable. Coming down on the MDMA while the DOx is still active can be quite anxiogenic.

Large amounts of GHB/GBL may overwhelm the effects of MDMA on the comedown.

There have been reports of risky serotonergic interactions when the two are taken at the same time, but MXE taken to the end of an MDMA experience does not appear to cause the same issues.

Large amounts of cannabis may cause strong and somewhat unpredictable experiences in combination with MDMA. Cannabis should be saved for towards the end of the experience if possible.

No unexpected interactions, though likely to increase blood pressure but not an issue with sensible doses. Moving around on high doses of this combination may be ill advised due to risk of physical injury.