FENCLONINE – THERAPEUTIC USE & SIDE EFFECTS
Fenclonine, which is known also by it’s chemical name para-chlorophenylalanine (PCPA), operates as a selective & irreversible inhibitor (substance added to prevent or reduce an unwanted reaction) of tryptophan hydroxylase, a rate limiting enzyme (catalyst) used in the biosynthesis of the neurotransmitter serotonin (5-HYDROXYTRYPTAMINE). Fenclonine acts to deplete endogenous levels of serotonin.
Fenclonine has been experimentally used to treat carcinoid syndrome, symptoms occurring relating to carcinoid tumors, but the extensive side effects, mostly hyper-sensitivity & psychiatric disruptions, have shut down further 
development.
It has been used in scientific research with animals to investigate the effects of the depletion of serotonin.