4-Methoxyamphetamine (Para-methoxyamphetamine, PMA) is a synthetic drug chemically similar to the recreational drug 3,4-methylenedioxymethamphetamine (MDMA or "ecstasy") and often replaces MDMA in tablets. Numerous cases of intoxication have been documented and fatal cases involving PMA have been described. PMA induces toxicity at lower doses than MDMA. Clinical symptoms specific to PMA poisoning include life-threatening hyperthermia, breathing difficulties, tachycardia, rhabdomyolysis, and acute renal failure. In the scarce studies conducted in laboratory animals, PMA has shown cardiovascular alterations in dogs, hyperthermia on a high ambient temperature, hallucinogen properties, and disruption of operant behavior in rats. A slight motor activity stimulation, lower than that induced by MDMA, has also been reported. The effects of PMA on brain neurotransmission are similar to those of MDMA, thus, PMA increases serotonin (5-hydroxytryptophan or 5-HT) release from the synaptic terminal and blocks its reuptake; it also acts upon noradrenergic and dopaminergic terminals but in a lesser proportion, and can also delay the metabolism of these monoamines by inhibition of monoamine oxidase (MAO)

ETRYPTAMINE (MONASE®), similar to the hallucinogenic tryptamines, is an inhibitor of monoamine oxidase, introduced for use as an antidepressant. It was withdrawn from the market due to problems with agranulocytosis and other side effects. However, it's activity is still under scientific investigation.