Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Para-Fluorophenylpiperazine (pFPP, 4-FPP; Fluoperazine, Flipiperazine) is a piperazine derivative with mildly psychedelic and euphoriant effects. IT has been sold as an ingredient in legal recreational drugs known as "Party pills", initially in New Zealand and subsequently in other countries around the world. PFPP has been found in vitro to act mainly as a 5-HT1A receptor agonist, with some additionally affinity for the 5-HT2A and 5-HT2C receptors. IT has also been shown to inhibit the reuptake of serotonin and norepinephrine, and to possibly induce their release. PFPP was originally discovered as a metabolite of the hypnotic antihistamine niaprazine in 1982, but was rediscovered in 2003 as a potential recreational drug, and sold as an ingredient in "Party pills" in New Zealand, under brand names such as "The Big Grin", "Mashed", and "Extreme Beans". SUbsequently it has continued to be used as an ingredient in black market "ecstasy" pills around the world.