Update on 1-benzylpiperazine (BZP) party pills.

N-benzylpiperazine (BZP) has become popular among recreational drug users as the major active ingredient of "party pills" due to its stimulant and euphoric properties. Before BZP legal restrictions, these pills were sold as a safe and legal alternative to classical amphetamines like ecstasy. New Zealand, given the size of its legal market prior to BZP control, is the country that most contributed to the knowledge about the patterns of use, motivations and positive and adverse effects resulting from its consumption, though the interest in BZP-party pills was observed all over the world. The use of these pills has been associated with hospitalizations for adverse events and continued availability over the Internet makes this intoxication a continued concern. This paper provides a review on the characteristics of BZP recreational use, specifically the target population, patterns and motivations of use, and evolution of legal status. Moreover, the in vivo and in vitro studies performed in order to understand its pharmacology, toxicology and kinetics are also discussed. Lastly, analytical methodologies for the identification of BZP in clinical and forensic settings are addressed.