A lethal dose of antidepressants caused a seizure-stricken Maidstone mum to suddenly collapse and die while shopping at a supermarket, a coroner heard.

Sandra Young, 42 fell to the floor before the eyes of her husband while shopping at Iceland store in The Mall, King Street in December.

Giving evidence at the inquest in Archbishop's Palace today, husband Peter Young said Friday, December 2 had started as just another day.

The couple, who would have celebrated their 20th anniversary this August, drove their son to Watford in north London for an exam and then had breakfast, before dropping him back at work in Aylesford and going shopping in Maidstone.

Everything was fine, Mr Young said - until as they reached the third aisle of Iceland at the Mall, Kings Street she had a seizure worse than any he had seen before.

"Personally I knew "that's it", he said.

Mrs Young had gone into cardiac arrest. She died despite the attempts of The Mall's first aiders and paramedics to save her.

The cause of death was given as fluoxetine toxicity.

The court heard how examination of Mrs Young's blood revealed fatal levels of the drug a prescription antidepressant often marketed under the brand name Prozac. High levels of quinine were also found.

There were being taken alongside a large number of other medicines for Mrs Young's various illnesses, including, depression, a personality disorder, obsessive compulsive disorder and fibromyalgia, a condition that left her in near-constant pain.

The former cleaning supervisor also suffered from non-epileptic seizures, which left her prone to bouts of uncontrollable shaking for which she had been recommended psychotherapy.

Mr Young, who left his job to become Sandra's full-time carer in 2011, told the coroner he helped manage his wife medicine, which was taken each morning and evening.

On the day of her death he said he had given his wife her usual three 20mg capsules of fluoxetine.

"I know what the amount was in the box so I know she hadn't taken more of it out," he said.

The court heard how a month before her death, Mrs Young had a seizure and collapsed at Tesco in Grove Green. She was taken to hospital but tests proved inconclusive.

Assistant coroner Katrina Hepburn found the cause of death to be drugs related.