Para-Chloroamphetamine

para-Chloroamphetamine (PCA), also known as 4-chloroamphetamine (4-CA), is a substituted amphetamine and monoamine releaser similar to MDMA, but with substantially higher neurotoxicity, thought to be due to the unrestrained release of both serotonin and dopamine by a metabolite. It is used as a neurotoxin by neurobiologists to selectively kill serotonergic neurons for research purposes, in the same way that 6-hydroxydopamine is used to kill dopaminergic neurons.

para-Chloroamphetamine has been detected as an apparent designer drug, along with the related 3-chloroamphetamine, which is even more potent as a releaser of dopamine and serotonin but slightly less neurotoxic.

The closely related N-methylated derivative, para-chloromethamphetamine (CMA), which is metabolized to para-chloroamphetamine in vivo, has neurotoxic properties as well.

China
As of October 2015, 4-CA is a controlled substance in China.