The authors report findings from a microdialysis study performed on rats, with microdialysate gathered from caudate. Levels of dopamine (DA), 3,4-dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), serotonin (5-HT) and 5-hydroxyindoleacetic acid (5-HIAA) were measured after i.p. injections of paramethoxyamphetamine (PMA), MDMA or methamphetamine. PMA was injected at 2.5, 5, 10 or 20 mg/kg, MDMA at 10 and 20 mg/kg and methamphetamine at 2.5 mg/kg. While both MDMA and PMA increased dopamine release and decreased DOPAC, PMA had no significant effects upon DA release except at the highest dose level (20 mg/kg), wherein it released as much DA as did MDMA. 10 mg/kg MDMA produced the same amount of DA release as 2.5 mg/kg methamphetamine. All doses of PMA produced significant decreases in DOPAC and HVA. Both MDMA and PMA released the same amounts of 5-HT at the two higher doses (10 and 20 mg/kg), whereas methamphetamine did not release appreciable amounts of 5-HT. PMA also decreased 5-HIAA after all doses. PMA and MDMA possessed similar monoamine release profiles in this study, but they had different effects on brain monoamine metabolites. Research findings suggest that PMA produces more fatalities in humans than MDMA because of probable MAOI activity, as indicated by its capacity to reduce amount of monoamine metabolites in brain, even when not stimulating the release of all monoamines. It is surprising that the authors did not examine norepinephrine (NE) release in this model. Contrary to statements appearing in this report, it seems extremely unlikely that people ever intentionally take PMA; most instances of use occur because it is falsely sold as ecstasy.