Randomised double-blind, placebo-controlled trial of the effects of the 'party pills' BZP/TFMPP alone and in combination with alcohol

J Psychopharmacol. 2010 Sep;24(9):1299-308. doi: 10.1177/0269881109102608. Epub 2009 Mar 27.


The objective of this study was to determine the clinical effects of party pills containing benzylpiperazine (BZP) and trifluoromethylphenylpiperazine (TFMPP) when taken alone and in combination with alcohol. The study was a randomised, double-blind, placebo-controlled trial conducted in a hospital-based clinic in Wellington, New Zealand. Thirty-five volunteers who had previously used party pills containing BZP were included in this trial. Participants received one of the following four treatments: 300 mg/74 mg BZP/TFMPP and placebo, 300 mg/74 mg BZP/TFMPP and 57.6 g (6 units) alcohol, placebo and 57.6 g (6 units) alcohol and double placebo. The primary outcome variable was a measure of driving performance, the standard deviation of lateral position (SDLP) measured at 6.5 h. Secondary measures included adverse events, cardiovascular effects, psychological function and delayed effects on sleep. The study was stopped early, after 35 of the planned 64 subjects had undertaken testing, because of severe adverse events that occurred in four of 10 BZP/TFMPP-only subjects, three of seven combined BZP/TFMPP and alcohol subjects, none of the 6 placebo subjects, and none of the 12 alcohol-only subjects. The overall rate of severe adverse events (defined as causing considerable interference with usual activity and/or rated by subject as severe) in those receiving BZP/TFMPP was seven of 17 (41.2%, 95% CI 18.4-67.1). The severe events included agitation, anxiety, hallucinations, vomiting, insomnia and migraine. BZP/TFMPP significantly improved the driving performance, decreasing SDLP at -4.2 cm (95% CI -6.8 to -1.6, P = 0.002). The effect of alcohol was to increase SDLP: 2.3 cm (95% CI -0.3 to 4.9, P = 0.08). BZP/TFMPP also resulted in increased heart rate and blood pressure and in difficulty in getting to sleep. BZP/TFMPP alone or with alcohol carries a significant risk of severe adverse events when taken in similar doses to those recommended by manufacturers.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Akathisia, Drug-Induced
  • Alcohol Drinking / adverse effects*
  • Alcohol Drinking / blood
  • Anxiety / chemically induced
  • Central Nervous System Stimulants / adverse effects*
  • Central Nervous System Stimulants / blood
  • Cross-Over Studies
  • Double-Blind Method
  • Drug Combinations
  • Early Termination of Clinical Trials
  • Female
  • Hallucinations / chemically induced
  • Humans
  • Male
  • Migraine Disorders / chemically induced
  • New Zealand
  • Nonprescription Drugs / adverse effects
  • Outpatient Clinics, Hospital
  • Piperazines / adverse effects*
  • Piperazines / blood
  • Psychotropic Drugs / blood
  • Psychotropic Drugs / toxicity*
  • Sleep Initiation and Maintenance Disorders / chemically induced
  • Somatosensory Disorders / chemically induced
  • Young Adult


  • Central Nervous System Stimulants
  • Drug Combinations
  • N-benzylpiperazine
  • Nonprescription Drugs
  • Piperazines
  • Psychotropic Drugs
  • 1-(3-trifluoromethylphenyl)piperazine