KEY POINTS:
The effects hit Phillip in an instant. An hour after downing a trial next-generation party pill, he suddenly felt "a surge of adrenaline into my heart".
Phillip's pulse went through the roof, he couldn't stop fidgeting and started scratching his own face.
About an hour later, Phillip was
in an ambulance struggling for breath on the way to hospital, where he ended up lying on the floor in emergency waiting for treatment.
"The first thing that went through my head was this is the stupidest thing we've ever done - taking unmarked pills in an envelope," Phillip told the Weekend Herald.
The Aucklander, aged in his mid-20s, was no stranger to the types of party pills already on the market.
He'd taken BZP about twice a month for the previous five years.
In fact, his track record taking London Underground products gave him and partner Dom the confidence to take part in the trial of the next-generation pills.
But the feeling Phillip got from the test pills was like nothing he'd felt before.
" He felt like he was dying," said Dom, who forced himself to vomit up one of the pills when he also started to feel sick.
The pair spoke on the condition of anonymity, angry the company's only response to their emails was an invitation to join another trial scheduled for late last month.
Two doses of two trial pills were sent to the pair in clear plastic bags in the post, with instructions to take two, then a further two if nothing happened.
"There was no warning, there was no 'don't do it on an empty stomach, don't drink, don't do this, don't do that'," said Dom. "It was just here you go, have a great time and report back to us the next day."
They said they had dinner and about 11pm on August 25 downed the pills, without having drunk any alcohol.
Phillip - who is fit and weighs almost 90kg - said it took an hour before he started to feel ill. "I just had this really awful feeling."
The pair went home and the situation deteriorated. "My body went completely numb, I felt like [when I touched my arm] I was touching somebody else. I couldn't breathe properly," Phillip said.
An ambulance officer apparently measured Phillip's blood pressure at twice its usual reading.
Dom said: "The next minute they [the ambulance officers] are like, 'Oh my God, we're off to the hospital, his blood pressure is, like, through the roof".
Medical records show Phillip's blood pressure was 220/120 when he arrived at hospital and he was "very anxious".
He was treated with a sedative before being discharged the next morning.
Phillip's discharge notes tell him to go to his GP in a week and "avoid party pill(s)!".
But on August 27, Phillip was back in hospital feeling dizzy and weak. He was again given medication to lower his blood pressure, which had shot up to 200/100.
The men haven't touched party pills since.
"We thought we were being responsible by not having any drugs, taking BZP, and trying something that's non-BZP," said Dom. "And now it's gone this way."
* Names have been changed.