4-Methylthioamphetamine

4-Methylthioamphetamine (4-MTA), also known as para-methylthioamphetamine (MTA), is a designer drug of the substituted amphetamine class developed in the 1990s by a team led by David E. Nichols, an American pharmacologist and medical chemist, at Purdue University. It acts as a non-neurotoxic highly selective serotonin releasing agent (SSRA) in animals. 4-MTA is the methylthio derivative of amphetamine. 4-MTA is a strong serotonin releaser similar to para-methoxyamphetamine (PMA), which can cause pronounced hyperthermia potentially resulting in organ failure and death. Therefore, the major neuropharmacological effect is an increased release of serotonin, and the inhibition of serotonin uptake of monoamine oxidase A (MAO-A). The combination of the releasing of serotonin from neurons and the prevention of breaking this neurotransmitter down again, leads to dangerous serotonin syndrome. The serotonin syndrome is a hyper serotonergic state, which can become fatal and is a side effect of serotonergic drugs. The symptoms of serotonin syndrome caused by 4-MTA are described in the Report on the Risk Assessment of 4-MTA Symptoms of the serotonin syndrome caused by 4-MTA Another effect is the increase of the secretion of several hormones, like adrenocorticotropic hormone (ACTH), corticosterone, prolactin, oxytocin, and renin induced by 4-MTA through stimulation of serotonergic neurotransmission. There has been suggested that 4-MTA because of its slow onset of action, is more dangerous than other designer drugs. Users of the drug rapidly take another dose because they assume the first was inadequate; thus increasing the possibility of an overdose.