A former patient of the serial killer Harold Shipman described yesterday how he invited her and her husband to dinner a week after apparently trying to kill her.

Elaine Oswald told the Shipman inquiry that when she read newspaper reports of his trial on 15 counts of murder in 1999 she began to realise that the doctor she thought until then had saved her life had in fact given her a potentially lethal injection.

At the dinner, he had explained that, when he discovered she had reacted violently to a drug he had prescribed, he had thrown her on the floor of her bedroom and given her the kiss of life, action which had left her with bruised ribs and a cut lip.

In a statement, Ms Oswald, aged 25 at the time of the incident, said Shipman had commented in a self-deprecating manner: "I'm sorry I almost broke your ribs in saving your life." He said he was more used to trying to resuscitate brawny miners.

Ms Oswald, now a professor of English at an American university, was one of Shipman's patients during his 18 months at a practice in Todmorden, West Yorkshire, before he was forced to resign because of his addiction to pethidine.

If Ms Oswald's claims are accurate, she might have become one of Shipman's earliest victims in a murderous career lasting a quarter of a century.

The inquiry in Manchester heard that Ms Oswald had seen Shipman on August 21 1975, a few months after he had joined the practice, to ask advice about a pain in her left side.

She was happy to have met a doctor who was young, understanding and easy to talk to. He had come round from his side of the desk to sit by her side, which she found less intimidating.

He diagnosed a suspected kidney stone and prescribed Dicanol, an opiate-based painkiller. He told her to take two tablets, go to bed and leave her front door open so that he could come in to take a blood test.

When he arrived after morning surgery, he shouted hello and went upstairs. "He was very interested in the antique furniture that we had in the bedroom and we were chatting generally," said Ms Oswald. He also explained that his wife, Primrose, and their son were outside in the car.

"I know he put a needle in my [left] arm but I'm not sure what he was doing. I assumed he was taking blood because that is what he had told me he was going to do. I seem to remember that he was moving across my body to do something to my right arm but I don't remember anything after that."

She woke up on the floor at the foot of the bed surrounded by Shipman, his wife, son and two paramedics. "I couldn't see properly," she told the hearing. "I couldn't stand. There were people slapping my face, shaking me telling me not to sleep. They were asking my name, what year it was, the date, who the prime minister was, saying, 'Don't go to sleep. Fight it, fight it'."

She spent four days in hospital, where she was treated "like the scum of the earth" because staff suspected she had taken an overdose. Shipman later told her he had acted swiftly because she was turning blue.

He explained that she had suffered a violent allergic reaction to Dicanol, that she had suffered acute withdrawal symptoms and that he wanted to write up her case in medical journals. At the dinner in his home, he gave her a form so that she could wear a bracelet warning of her allergy to narcotics. "For 25 years, I have been afraid to take any kind of drugs, even in childbirth and during laryngoscopy," she added.

She moved from Todmorden in 1975 and later emigrated to the US. In 1999 she read in reports of Shipman's trial that he had given his victims lethal injections. She contacted police and told them: "For all this time I have truly believed that Dr Shipman had saved my life. However, when I read about his modus operandi, I realised that I may have been one of his victims."

Caroline Swift QC, counsel for the inquiry, said: "If Shipman did inject Mrs Oswald with the intention of killing her, he was running a very considerable risk.

"The death of a previously healthy 25-year-old woman would have attracted a considerable amount of attention locally and would have inevitably resulted in a postmortem and toxicology tests."