Print PageStanley Valentine Whiley, 67, was a resident at the Tamar Park nursing home at Legana when he died in March 2010.
Mr Whiley had been prescribed morphine sulphate at between 2.5 and 5 milligrams.
On her first shift as an registered nurse, Julie Lord instead drew 25 milligrams, 10 times the dosage she had intended to give.
Forensic pathologist Dr Christopher Lawrence told the inquest Mr Whiley also had heart disease and had suffered a stroke.
Dr Lawrence says while the dosage was only just within the fatal range, he could not ignore the morphine as a contributing factor.
