Sydney hospital apologises after death of 88-year-old woman.

Sydney’s North Shore Private Hospital has apologised to the family of an 88-year-old woman who died after being given a massive overdose of prescription medication.

Deputy state coroner Magistrate Harriet Grahame is investigating the death of Audrey MacGregor in 2013.

The grandmother of 17 was being treated for pneumonia and other health complaints at the hospital when she was given five milligrams of hydromorphone, a derivative of morphine – 10 times the prescribed dose.

The court heard that when the error was discovered, Mrs MacGregor was given another drug to counter the effects of the medication.

Her daughter, Jenny Compton, said: "Mum never regained consciousness. She died later that afternoon."

Cause of death was complications from pneumonia

A post-mortem examination found the cause of death was complications from pneumonia.

"There is no objective evidence ... that she received a toxic amount that would have contributed to her death," said Dr Rebecca Irvine, a Forensic pathologist at the Department of Forensic Medicine.

"I believe she was dying ... she was starting to fade even before she was given the hydromorphone."

Other experts said this was clearly an overdose - but it is not certain the drug killed Mrs MacGregor.

Palliative Medicine Physician Dr Ghauri Aggarwal told the court: "It was an inappropriate dose ... yes it may have played a part in her death. Any patient given an incorrect dose would suffer respiratory depression."

The inquest heard Mrs MacGregor was prescribed the medication to slow her breathing from a rate of 55 breaths per minute.

Dr Irvine said "Someone who has a respiratory rate of 55 ... I can not imagine they would not be in distress. That is a person fighting to breathe literally every second."

Dr Aggarwal said there may be confusion regarding the potency of some opiod medications.

"The bigger issue is the proper education and a change in approach to opiods in NSW ... and understanding pain management and opiod usage," she said.

North Shore Private Hospital 'deeply saddened'

The hospital released a statement that said: "North Shore Private Hospital is deeply saddened by this incident and has apologised to the patient's family. The hospital has cooperated fully with the coroner's investigation.

"At the time of the incident, the hospital promptly undertook its own internal review and has already implemented several improvements such as improved medication labelling; increased education of clinical staff; and policy changes that limit prescribing to specific specialty medical practitioners."

Mrs MacGregor's son Philip MacGregor said he believed the death had upset hospital staff.

"I'm concerned for their welfare because we don't hold a grudge against them" he said. "I know they were trying to help mum and it didn't work out."

Mrs MacGregor's husband Walter said he had enjoyed 61 years of marriage.

"She was a wonderful woman" he said. "I miss her greatly".

"We still think North Shore Private is a wonderful place. But they did make mistakes."

The inquest continues.

This post originally appeared on the ABC.

© 2016 Australian Broadcasting Corporation. All rights reserved. Read the ABC Disclaimer here.