The daughter of 86-year-old Eileen Cowles said the family were "relieved" after the narrative verdict following a two-day inquest which heard a GP massively overprescribed tablets to treat a Vitamin D deficiency.
Cancer survivor Mrs Cowles died on April 17 2015 after suffering intestinal bleeding caused by high levels of calcium in her blood after she was mistakenly prescribed two of the tablets a day instead of the correct dose of two per month.
Returning a narrative verdict, area coroner Jonathan Leach said Dr Claire Wiles of Park Row Medical Centre, Guiseley, had failed to carry out basic checks when issuing the repeat prescription.
Mr Leach said Dr Wiles did not consider whether the medication was appropriate, whether the dosage and frequency were appropriate and did not check a medical reference book when Mrs Cowles' care home and a pharmacist both queried the dosage.
Returning a narrative verdict Mr Leach, said: "These failures collectively amounted to a gross failure, which caused the deceased's death."
Mr Leach said that the failures "constitute neglect."
After the inquest verdict, Mrs Cowles' daughter Christine, said: "We are relieved that four years after our mum's death those accountable for her death have had to explain themselves.
"Our mum died because five repeat prescriptions were wrong.
"We hope that people will take note of this, especially because she died of a Vitamin D overdose. Please always check yours and your family's prescriptions."
Eileen Cowles was a retired pub landlady who ran pubs in Leeds from the 1970s to the 1990s, including the Old Kings Arms in Horsforth and the Fox and Hounds in Bramhope.
Mrs Cowles had a history of vascular dementia and had previously undergone extensive facial surgery to remove a tumour after suffering from cancer in 1996.
Her son David, 57, said: "She was a warrior. She never moaned, she got on with life.
"Even when she went through her face cancer, she never gave up."
Wakefield Coroner's Court heard the correct prescription of the drug called colecalciferol had been issued after Mrs Cowles was treated at Leeds General Infirmary after fracturing her left hip following a fall at home in September 2014.
The colecalciferol tablets were prescribed to strengthen her bones and the prescription stated she should take two tablets - 40,000 units of the drug - per month.
The inquest heard after her fall, Mrs Cowles, previously of Cookridge, could no longer live independently.
She moved to Primrose Court Care home in Guiseley and her new GP practice was Park Row Medical Centre in Guiseley
Dr Claire Wiles, of Park Row Medical Practice told the inquest she made a mistake while transcribing Mrs Cowles' repeat prescription in November 2014.
Dr Wiles had also confirmed her wrong prescription of two tablets - 40,000 units per day of colecalciferol - was correct after it was queried by both the care home where Mrs Cowles was being looked after and the pharmacy that dealt with the prescription.
The inquest was told Dr Wiles later went on maternity leave.
Subsequent repeat prescriptions for two tablets a day of colecalciferol continued to be signed off at Park Row Medical centre from December 2014 to February 2015.
After giving evidence during the inquest, a visibly upset Dr Wiles made a tearful apology to Mrs Cowle's family, telling them: "I just want to say I'm sorry. I am sorry to the family."
Dr Wiles was newly qualified and had only been working as a GP at Park Row Medical Centre in Guiseley for just over a year when she made the mistake.
The inquest heard the dosage given to Mrs Cowles would have instead been appropriate for a patient who had chronic liver disease.
The increased dose over a number of months led to Mrs Cowles suffering a condition called hypercalcimia, where there is too much Vitamin D in the blood.
She died after suffering intestinal bleeding caused by the high levels of calcium found in her blood as a consequence of the over prescription.
Her family only discovered the fatal mistake after finding papers while clearing out her room at Primrose Court after her death.
Dr Wiles said she had used The British National Formulary - a United Kingdom pharmaceutical reference book - to decide on the dosage applicable to the patient.
She had not seen a hospital discharge advice note prior to signing the prescription and agreed that was an "error."
A repeat prescription enquiry was made on November 26, 2014, by Primrose Court care home home staff as they were confused by the lack of dosage given on the prescription from the GP.
A note returned from the practice said ‘20,000 capsules take two’ - but no indication was given as to whether that was daily, weekly or monthly.
Her "high" dosage levels were then questioned by pharmacists at Boots at Colton - but they were again told by Dr Wiles to give Mrs Cowles two tablets per day instead of per month.
Dr Wiles said when she looked at the BNF manual, she had "taken it to confirm" the dosage she had prescribed.
Dr Wiles agreed she had misread the page and prescribed the wrong dosage for someone who would have had "chronic liver disease".
The GP was also criticised in a report commissioned by West Yorkshire Police, which was read to the inquest
Expert witness Neil Lloyd-Jones wrote in the report: "Dr Wiles incorrectly stated the dosage to be daily rather than monthly.
"The fact Dr Wiles wrote out an incorrect prescription and failed to put in place a strategic management plan, in my opinion, the standard medical care would fall below the common acceptable medical practice."
GP Ibrahim Syed of Park Road Medical Centre at Guiseley previously told the inquest the dosage was a "mistake" and he would have scrutinised the repeat prescription in more detail if he wasn't pressed for time.
He said: "I think ultimately I had not spotted the fact the prescription was erroneous. Regretfully I had not picked up on the fact this was not a maintenance dose.
"I think it's human error, it's a case of having to scan a large number of prescriptions everyday compounded by trust I put in my colleagues.
"I think when you are less pressed for time it might be I would have been able to spot the erroneous dose. It was almost like a needle in a haystack.
"Regardless of whether you are busy or not, I put a lot of faith in my colleagues when they are setting up repeat prescriptions and it was further exacerbated by the workload at the time."
Former Home Office pathologist Dr Richard Shepherd said he had not encountered hypercalcimia as a cause of death in this way in is 35-year career.
Dr Shepherd said he could not rule out that the intestinal bleeding was spontaneous, but added: "I think it's much more likely than not that it was due to the hypercalcimia or a side effect."