KEY POINTS:
The 64 human lab rats turned up for testing at a private hospital in Wellington.
On empty stomachs, they swallowed party pills, some washed down with vodka.
They were taking part in the short-lived, Government-funded study into the effects of BZP (benzylpiperazine) and TFMPP (Trifluoromethylphenylpiperazine), the main ingredients in party pills.
New Zealanders have consumed 26 million doses since the synthetic stimulants became popular around the turn of the century.
Around 5 million pills are expected to be sold this year, with the overall value of the industry placed at around $20-30 million.
But it's last call for the party pill industry.
Associate Health Minister Jim Anderton hopes a bill to outlaw the pills will be ready for introduction to Parliament soon and expects the legislation to pass by Christmas, putting BZP and TFMPP-based pills in the same category as cannabis.
BZP is already banned in Australia, America and Japan.
Mr Anderton said the human trial showed the adverse effects of BZP and TFMPP, including "insomnia, headaches, nausea and anxiety".
"Seizures have also been reported. There is a potential for severe toxicity in some individuals, which has been reported after relatively low doses. The effect of long-term use of party pills containing piperazines is as yet unknown."
But the Social Tonics Association of New Zealand, which represents party pill manufacturers, says the government ban is bad decision-making.
The industry - which has hired public law specialists Chen Palmer and spent $300,000 to stop the ban - claims the Wellington trial was flawed and other research was incomplete.
The industry maintains that, properly regulated and used safely, the pills are less harmful than alcohol and reduce demand for illegal drugs like methamphetamine and Ecstasy.
The Herald has asked for the papers considered by the Expert Advisory Committee on Drugs before it recommended Mr Anderton push for a ban.
Most researchers and institutions, including the Medical Research Institute, declined because the studies have not been peer-reviewed or published in journals.
A source close to the Wellington trial said researchers had a "pre-set" idea that party pills were unsafe and there was some concern about the doses given.
The participants had all taken party pills before. They were given capsules each containing 75mg of BZP and 18.4mg of TFMPP, derived from two different brands of party pills.
Two capsules were taken, then two more in two hours - for a total dose of 300mg of BZP and 73.6mg of TFMPP.
"If you're taking psychoactive drugs in an environment in which you're not totally familiar, and out of the context of which you normally take them, and out of your social circle and the happy buzz ... they will affect you differently," the source said.
"When you're looking at a new drug and whether or not it has some toxicities you start off with a very low dose and give that to people. If they tolerate that you give them a little more dose and see if they tolerate that, and you step it up until you start to get some signs there might be adverse reactions. Then you stop."
According to the trial report, leaked to the Herald, the doses were "well within the range of doses normally taken", based on recommended doses on product labels.
Subjects who mixed pills with alcohol - pill packets carry warnings not to do so - were given six drinks of vodka and orange, containing 30ml of vodka, over three hours.
All participants were asked to fast from at least six hours before test day, which was conducted over 12 hours and included lunch, dinner, fruit and cheese boards.
Driving performance was assessed on a simulator, and participants filled in a computerised questionnaire and sleep diaries.
The most commonly reported side effects from the group's previous use of party pills were dry mouth, nose and throat, loss of appetite, headache, feeling cold, sweatiness and nausea.
Researchers halted the study after four out of 10 people in the straight BZP/TFMPP trial had experienced "severe adverse events", as did three out of seven in the pill/alcohol trial.
There was also severe vomiting, confusion and insomnia (37 hours), although the report does not say how many of the effects were felt by each person.
"The severe acute effects included anxiety, agitation, and hallucinations whereas the delayed effects refer to the insomnia, headache, fatigue and malaise which occurred in the day or two after dose ingestion.
"The latter are commonly referred to as a 'bad hangover', which causes many people to limit their use of party pills," according to the report.
Party pills alone did not cause subjects to vomit, but they did when combined with alcohol.
The report concludes that party pills used alone or with alcohol "carries the risk of severe adverse effects", and that a combination of BZP and TFMPP "may have marked effects on cardiovascular function and sleep".
The source said it was impossible to extend the findings to all people who use party pills.
"Within the study it found what was true for those particular people in that particular context at that particular time, but that doesn't have a lot of validity for a lot of people who weren't in that environment at that time."
The Social Tonics Association says Mr Anderton and the Expert Advisory Committee on Drugs should have dismissed the findings of the Wellington trial.
Expert advice the association received from Australian researchers said the study was "fundamentally flawed" and "incapable" of establishing that BZP posed a moderate risk of harm.
Dr Alex Wodak, director of drug and alcohol services at St Vincent's Hospital in Sydney, and Dr Michael Dawson, Sydney University of Technology head of chemistry, materials and forensic science, said the rate of side effects reported by the "seasoned" party drug users in the study were "so high as to be difficult to accept".
The pair were critical of the "clinical environment" in which the study was carried out, saying it was more likely to exacerbate negative effects and diminish pleasurable effects.
The men said it was "bad practice" to give participants off-the-shelf pills mixed together, rather than a pure substance.
"It leaves open the possibility that adverse effects noted in the study may have resulted from the other components of the capsule," they said, referring to the fact that researchers did not analyse the doses of various amino acids, antioxidants, minerals and vitamins also contained in party pills selected for the trial.
Among the other research the Expert Advisory Committee on Drugs considered was a study by Otago University's National Poisons Centre into cases of poisoning due to piperazine-based party drugs.
The university said it could not release the study because it was in the peer-review stages after being submitted to an international toxicology journal.
An Auckland University paper, "Legal Herbal Highs: A Qualitative Study of their use by Young People aged 16 to 24", is also yet to be released.
But according to an extract, the 2006 study found most users knew about negative effects of party pills and many had experienced them - for example raised heart rate, inability to sleep and upset stomach.
Users had varying levels of knowledge about what was in party pills, and about safe use. They commonly mixed party pills with alcohol, and with other drugs.
However, no one in the study had accessed health services for effects. Of those who had cut down or stopped using, none had found any difficulty.
Treatment services workers reported few, if any, issues with young people and party pills.
Another report considered by the advisory committee - "Patterns of use of legal piperazine party pills containing Benzylpiperazine (BZP) and Trifluromethylphenylpiperazine (TFMPP) and adverse effects in a population sample in New Zealand" - is still being worked on.
The study comes from Massey University's Centre for Social and Health Outcomes Research and Evaluation, which published comprehensive research into party pill use in its 2006 National Household Survey of Legal Party Pill Use.
The survey, also considered by the advisory committee, found one in five people had tried party pills.
Dr Bruce Russell from Auckland University's School of Pharmacy says it has yet to be confirmed if BZP is safe or not.
"There are only two published trials in total that report what BZP does to people and they are both from 1973 and are far from comprehensive," he said.
"There are no published trials about the effects of TFMPP in people at all."
Dr Russell is conducting a number of studies into BZP and TFMPP.
"We've had very little problem with adverse effects even though we are using close to the maximum recommended dose of BZP, on its own, by the party pill industry. We have taken body weight into consideration so comparatively small people aren't getting a huge dose."
Dr Paul Gee, head of emergency medicine at Christchurch Hospital, believes a decline in the number of patients showing up at the emergency department with BZP-related problems is due to more people becoming aware of the risks.
"We are still seeing a hardcore of patients who repeatedly have seizures while using BZP but continue to take it. This is evidence of addiction."
Social Tonics Association spokesman Matt Bowden says BZP will be "banned on emotion and public opinion", not proper scientific evidence.
The industry will continue to make its case, preparing extensive submissions for the select committee process, and work with the Government to develop a framework for future products.
"It's not a foregone conclusion. The health select committee is there to do a full consultation with the public, a full investigation. All of the research should get looked at at that point," Mr Bowden said. The industry had paid $10 million in taxes, which would cover the administration of regulations governing the manufacturing, marketing and sale of party pills.