"Information on the toxicological aspects of many piperazines listed in this group remain limited. Further research is required to provide evidence on short and long term health-effects associated with the use of these substances. Current knowledge comes from user reports, studies in animals, limited human studies, and clinical observations.
"Piperazines have been found to act as stimulants as a result of dopaminergic, noradrenergic, and predominantly serotoninergic effects produced in the brain. BZP produces toxic effects similar to amphetamine and other sympathomimetics, although, according to animal studies, its effects are less potent than amphetamine, methamphetamine and MDMA.66 TFMPP, used in conjunction with BZP, has been reported to produce some of the effects of MDMA, but with a lower potency,67 while mCPP has been indicated to produce similar stimulant and hallucinogenic effects as MDMA.68
"In New Zealand, toxic seizures and respiratory acidosis after the use of BZP alone or in conjunction with other drugs were reported from three patients.69 Another study of 61 patients reported toxic effects of BZP, with two cases presenting life-threatening toxicity.70 Hyperthermia, rhabdomyolysis and renal failure associated with BZP ingestion have also been reported.71 In the United Kingdom, self-terminating grand mal seizures72 after the use of BZP have also been reported.73
"Between 2004 and 2008, six fatal cases involving piperazines use were reported in Europe. Two of the cases involved the use of BZP in conjunction with TFMPP and none referred to the use of piperazines alone.74 BZP and TFMPP were also associated with 19 fatalities between 2007 and 2010.75 While reported effects of mCPP include the serotonin syndrome, no fatal poisonings from mCPP have been reported so far.76 Similarly, toxic effects from the use of TFMPP alone have not been documented.77"
UN Office on Drugs and Crime, "The Challenge of New Psychoactive Substances: A Report from the Global SMART Programme" (Vienna, Austria: UNODC Laboratory and Scientific Section, March 2013), pp. 12-13.