Bobbi Kristina Brown
Bobbi Kristina and boyfriend Nick GordonMaury Phillips/Getty Images For A E Networks

Bobbi Kristina Brown was hooked on a lethal cocktail of drugs in the days before she was admitted to hospital, a high school friend of the 22-year-old star has claimed.

According to Steven Stepho, the daughter of the late Whitney Houston and Bobby Brown was battling a drug addiction and had a tumultuous relationship with boyfriend Nick Gordon, who has a "short fuse".

Brown has been in a medically-induced coma since she was found face down in a filled bath at her home on 31 January. Gordon administered CPR until the ambulance arrived on the scene and continued to carry out lifesaving procedures.

Speaking to The Sun, Stepho alleged that the reality star was in toxic relationship, claiming that couple could spend a thousand dollars a day on drugs a day on heroin, Xanax, pot and heroin substitute Roxicodone.

"Bobbi and Nick would spend a lot on drugs every day, it just depended on how much money they had. It wasn't unusual for them to spend $1,000 [£676] a day on drugs," he said.

"There were times when it got really bad — they would be completely passed out for hours, just lying there on the bed. There were times when she would be so knocked out she would burn herself with a cigarette and not even notice. She was always covered in cigarette burns."

Previous reports suggested that Brown was "in and out" of rehab for three years after her mother's sudden death. Stepho, who initially denied having any part in his friends' drug habit, insisted that he didn't want to be painted as the bad guy and denied being Brown's main dealer.

"I don't want my character and reputation to be ruined," he told Radar Online. "That part of my life is way in the past. I made mistakes and have paid my dues for those mistakes. I have a great job and a child on the way and really can't have me looking like a bad person."

"I helped them get it sometimes, but not regularly," he added.

Brown's situation echoes the death of her mother on the eve of the 2012 Grammys. Houston passed away on 11 February 2012, when she was found unresponsive in a bath of a Beverley Hills hotel. A coroner later concluded her death was as a result of accidental drowning, though heart disease and cocaine use were contributing factors in her death.

Stepho's claims comes days after Gordon admitted to battling addiction during an intervention with TV doctor Dr Phil. The 25-year-old had appeared on the show after posting a series of worrying messages on Twitter that appeared to suggest he was suicidal. In an emotionally charged interview, Gordon broke down and threatened to kill himself.

Gordon has reportedly been banned from visiting Brown as police continue investigating the events leading to her being rushed to hospital.