serotonin–norepinephrine–dopamine releasing agent serotonin–norepinephrine–dopamine releasing agent a serotonin–norepinephrine–dopamine releasing agent (sndra), also known as a triple releasing agent (tra), is a type of drug which induces the release of serotonin, norepinephrine/epinephrine, and dopamine in the brain and body. sndras produce euphoriant, entactogen, and psychostimulant effects, and are almost exclusively encountered as recreational drugs. further information: serotonin releasing agent, norepinephrine releasing agent, and dopamine releasing agent a closely related type of drug is a serotonin–norepinephrine–dopamine reuptake inhibitor (sndri). stahl uses the term "trimonoaminergic modulators" (tmm) in his work. examples of sndras examples of sndras include specific amphetamines such as mdma, mda, 4-methylamphetamine, methamphetamine (in high doses), certain substituted benzofurans such as 5-apb and 6-apb, naphthylisopropylamine; cathinones such as mephedrone and methylone; tryptamines such as αmt and αet; along with agents of other chemical classes such as 4,4'-dmar, and 5-iai. αet and αmt are of special notability among sndras in that those tryptamines were once used as pharmaceutical drugs, specifically as antidepressants, but were withdrawn shortly after introduction in the 1960s due to problems with toxicity and recreational use. such tryptamines were originally thought to act as monoamine oxidase inhibitors (maois) before the signature monoamine-releasing actions were elucidated. many years after being withdrawn, αet was also determined to produce serotonergic neurotoxicity, similarly to mdma and various other sndras; the same is very likely true for αmt as well, although it has not specifically been assessed.