Deborah Clarke was found dead in the utility room of her shared accommodation in Cecil Road, Kingsthorpe, last December.

Miss Clarke's parents had expressed concerns their apparently healthy daughter may have suffered a fatal side-effect of an anti-smoking drug.

She had been prescribed a course of Champix by her doctor several weeks before she died to help her quit her 30-a-day cigarette habit.

But although consultant histopathologist Angus Molyneux recognised a potential link between the drug and heart problems, he said it had not been a direct cause of her death.

He added: "In a few instances a heart attack has been reported in association with the drug.

"We have eliminated this through post mortem examination, but clearly we can't rule out the possibility that the drug may have contributed to the onset of a dysrhythmia.

"But this is unlikely to have caused the fatality."

Coroner Anne Pember recorded an open verdict.