A teenager whose death almost led to the permanent closure of one of London’s most popular nightclubs was poisoned by a high dose of the drug MDMA, an inquest has heard.

Jack Crossley, 18, had 2.2 micrograms of the drug in every millilitre of his blood – more than enough for a fatal reaction – when he died on 6 August 2016 after visiting Fabric in Farringdon, a toxicology report found. Paramedics took him to Royal London hospital where he died after suffering a fatal cardiac arrest .

He was the second teenager to die within six weeks after visiting Fabric. The last time Crossley and his friends had visited the club was the night that Ryan Browne, also 18, collapsed and died after taking MDMA there, the inquest was told.

His death led to the club losing its licence after an application by the Metropolitan police. It will reopen this weekend after a high-profile campaign backed by some of the biggest names in dance music.

Poplar coroner’s court heard how Crossley and two friends had spent the night dancing and taking crystal MDMA that had been obtained by Crossley from a friend in his home town of Worcester Park, Surrey.

Josh Green, Crossley’s friend, told the court how they had smuggled the drugs into Fabric by concealing them in their underwear. He said they had dosed themselves throughout the night, starting around midnight with quantities wrapped in cigarette rolling papers, then swallowed.

“We kept doing that every now and then, and then after that we had run out at a certain point,” Green said. “I felt personally myself [that] it should be fine and we didn’t need any more that night.”

The court heard, however, that Crossley was offered a chance to buy more. Joe Ryan, who was also with Crossley, said: “Someone approached Jack while we was at the bar and said ‘do you want any more?’ Jack asked me and Josh; I said yes.”

It was as the group decided to leave the club at about 5.30am that a security guard noticed that Crossley, who was being helped up the stairs by Ryan and Green, appeared to be unwell.

In a statement, Caroline Smith, a paramedic working for Fabric, said a doorman had led Crossley into the club’s medical bay at 5.28am. She said she read his pulse at 190BPM, well above what she would expect even for someone who had been drinking or even taken ecstasy.

“I was very concerned at Jack’s appearance together with his very high heart rate,” Smith said. “I said … this needed to go in now, meaning we needed to get an ambulance.”

Crossley’s temperature rose to 39.9C initially and then to 41.4C less than 15 minutes later, the court heard. Smith said attempts to cool Crossley with wet towels and ice were hampered by his increasing agitation. When an ambulance arrived, paramedics took Crossley inside and continued to work on him, treating him with intravenous tranquillisers and cold saline. After he suffered a cardiac arrest inside the ambulance he was taken to the Royal London hospital.

Dr Karim Ahmad, who treated Crossley on arrival, said his patient’s temperature was initially “unrecordably high”, although medics were later able to take a reading of 42C. “Aggressive cooling protocols were initiated, but he was unstable,” Ahmad said in a statement. Crossley suffered another cardiac arrest at 7.42am and medics gave up resuscitation attempts at 8.58am, Ahmad said. “I believe that the metabolic effects of the drug reaction were so severe that there was nothing else that teams could have done that would have had a significant effect on the outcome,” the doctor added.

Toxicologist Joanna Hockenhull, who analysed samples of Crossley’s blood after his death, found methylenedioxymethamphetamine (MDMA) in his blood at a concentration of 2.2 micrograms per millilitre, “well within the fatal range”, the court heard. Pathologist Lindsay Clarke later recorded the medical cause of death as MDMA toxicity.

Luke Laws, the general manager of Fabric, said the club had taken a range of measures to try to prevent a repeat of Crossley’s death, from changing the lighting system to ensure there were no dark corners to retraining security staff to conduct more stringent searches. However, he added that there would have been no way to detect Crossley’s drugs hidden in his underpants.

Laws, who faced a persistent cross-examination from friends and family of Crossley, said more was needed to be done to warn youngsters of ecstasy, which has become increasingly pure in recent years, and to encourage responsible use where it cannot be prevented. “The Home Office have issued guidance where they expect the police to enforce the law, which is at odds with certain practices which can help get this information out there, so there is a problem between crime and and disorder and public health,” he said.

Recording a determination of drug-related death, Mary Hassell, the coroner, echoed Laws’ call for a greater emphasis on public health. She said: “I’m very conscious that certainly there are issues with Fabric, but this is a problem that’s much wider than that. It’s much wider than one nightclub.

“I think it was Mr Laws who said that he recognises the conflict between crime and disorder and public health and I can see that and every time I sit in an inquest with a drug death, and I sit in many, in nightclubs, out of nightclubs, in people’s homes …

“It strikes me very forcibly that there is this struggle between the criminal justice system and public health, and it’s something that we as a society are grappling with.”

