A patient has died after being given the wrong medicine at the Norfolk and Norwich University Hospital (N&N) in a rare incident under investigation by health chiefs.

The man died in October after being discharged from the hospital with the incorrect medication.

The hospital stressed the case was extremely unusual and the results of its investigation will be sent to its patient safety board.

The death was disclosed in a report which will go before the hospital's board at a meeting on Friday morning.

The mistake was one of 133 medication errors at the N&N in October, an increase on the monthly average of 95.

The majority of errors are picked up and do not lead to any harm to patients, but in October six medication errors, including the one that caused the death, had harmful consequences.

One of the patients had hypoglycaemia (low blood sugar levels) because they weren't prescribed a drug called prednisolone which is used to treat allergies.

Another patient had symptoms of hypocalcaemia (low calcium levels in blood) because they weren't given a drug called Sandocal after an operation on their thyroid gland.

Another had to stay in hospital because they were given the wrong dose of an anti-epileptic drug, while one patient took longer to be resuscitated as they had an anaphylactic reaction to a drug where an allergy had already been suspected.

The death is the first known case in recent history of someone at the hospital dying after being given the wrong medicine.

Professor Krishna Sethia, medical director at the N&N, said: 'Nationally and internationally medication errors are the most common cause of harm to patients in hospital. To avoid these we have a rigorous programme of staff training and investment.'

All medication errors are recorded and the number of mistakes has been rising.

The hospital said in a report in March the increase was down to their 'culture of transparency' which encourages the reporting of mistakes.

The N&N aims to cut down medicine errors by prescribing drugs electronically. In two wards – Brundall and Elsing – medics now use laptops attached to drug trolleys to record prescriptions, check patient records and check for allergies.

The ePrescribing project is part funded by £1.74 million from the Safer Hospitals, Safer Wards Technology Fund which is sponsored by the Department of Health.

Professor Carol Farrow, clinical director of Pharmacy Services at the N&N, said: 'Feedback so far has been great, the clinicians are very enthusiastic about using the new system.'

Professor Farrow added the system would cut out many but not all mistakes.

Dr Martyn Patel, who is using the new system on a dementia ward, said: 'It is much easier for doctors because we can access all medications on a single screen and the built-in automatic allergy checker makes prescribing safer for patients.'

Laptops will be added to two other wards early next year.

•Would you like to pay tribute to the man? Email tom.bristow@archant.co.uk.

• The hospital's board meets in public on Friday at 9am. There will be an update on the quality, safety and performance of hospital services.

Space is limited at the meeting, but members of the public who wish to attend should contact the communications office on 01603 287200 or e-mail: communications@nnuh.nhs.uk