Ecstasy pills in recreational settings often contain MDMA, but many also include other drugs like MDEA and methamphetamine. The amount of MDMA per pill varies widely, from 0 to 245 mg. Users typically consume between half a pill and five pills in a session, with total MDMA doses reaching up to 280 mg. Plasma concentrations of MDMA rise with the number of pills consumed and the cumulative dose. Taking multiple pills over several hours leads to sustained high MDMA levels in the blood, exposing the brain to the drug for longer than single-dose studies would suggest.
Co-administration of MDMA with the monoamine oxidase inhibitor moclobemide increases extracellular serotonin in the rat striatum to levels comparable to those produced by PMA, a more toxic recreational drug. MDMA alone raised serotonin by 590%, PMA by 360%. When moclobemide was given before MDMA, serotonin increased by 980%, and serotonin-related behaviors also increased. PMA is also a potent MAO-A inhibitor, which may explain its greater toxicity. These findings suggest that combining MDMA with moclobemide may produce serotonin-related toxicity similar to that of PMA.