A woman suffered an overdose when a nurse accidentally administered between five and 10 times her usual dose of fentanyl after mistaking it for anti-nausea medication.

The dangerous oversight was calmed by administering the reversal drug Naloxone but the patient, who receives dialysis treatment three times a week, was still left in excruciating pain.

Nurses had to hold the woman down as she was “screaming and throwing [her] body all over the bed,” findings by deputy Health and Disability Commissioner Vanessa Caldwell, who heard a complaint about the error, said.

According to her decision released today, the woman was at Middlemore Hospital in 2019 to undergo her regular dialysis treatment. She had multiple health issues, suffering from kidney disease, type 2 diabetes, acid reflux and seizures.

She was also reliant on opioids, prescribed for chronic pain relief, and took them before undergoing dialysis treatment.

At 7am on an October morning, she arrived at Middlemore for her scheduled appointment. A nurse referred to in the decision as ‘Nurse B’ was assigned the woman’s primary nurse.

Nurse B, alongside colleague Nurse C, had collected the medication prior to her arrival and placed it by the patient’s machine. But the syringe designated for fentanyl was not labelled as such, as is required under the law.

The woman, in her 50s, told Nurse B she did not want any further oxycodone (an opioid painkiller) as she had vomited earlier.

But she asked to be administered Ondansetron, an anti-nausea medication, before her normal dose of fentanyl. She typically took both drugs before treatment.

Nurse B, under the impression his colleague was busy at the time and so could not provide the mandated check by a second nurse, obliged. He intended on seeking another nurse to undertake the check before he administered the fentanyl.

The two drugs were placed in a dish together. Photo / File

He drew 100 micrograms from the ampoule and administered it to the patient. The drug was mistakenly identified as Ondansetron when it was actually fentanyl. Both ampoules were next to each other in a dish.

The patient’s typical fentanyl dose would only be between 10 and 20 micrograms.

Just minutes later, the woman reported feeling dizzy and sleepy. The nurse immediately realised his error and informed the unit’s clinical coach. He then told the patient and apologised.

Two to three nurses stayed near the woman, including Nurse B, who told the deputy commissioner he had wanted to continue his observations and take care of her.

The overdose was not noted on her medication chart, Counties Manukau District Health Board told Caldwell, stating staff had been busy caring for the woman.

The renal registrar ‘Dr D’ noted shortly after the overdose, the woman felt “alright”.

“Blood pressure and respiratory status fine. Pupils small. Vague and appears drowsy,” he wrote. Dr D then made the decision to prescribe naloxone to reverse the effects of the fentanyl.

The drug is designed to be administered at 40 micrograms every two minutes until the desired result is achieved. The patient was administered 40 micrograms at 7.51am, and again at 8.01am.

While the woman initially felt fine, she began to feel the effects of opioid withdrawal after the naloxone almost entirely countered the effects of the fentanyl.

“I remember being in severe pain all over my body, screaming and throwing my body all over the bed … I had gone into severe withdrawal symptoms. My pain in my body and legs were overwhelming,” she told the deputy commissioner.

“The naloxone IV had stripped me of all the IV fentanyl in my body and I was going into shock. The pain in my body was off the wall. I just thrashed around while nurses tried to hold me down.”

Around 9am, the woman requested more fentanyl, which was administered.

The deputy commissioner noted that after the administering of the naloxone, the patient’s vital signs weren’t recorded again until nearly three hours later. The medical team said despite the lack of records, the patient was closely monitored.

The woman told Caldwell that this wasn’t the first time incorrect drugs had been administered to her, and she didn’t want it to be “sweeped under the rubbish bins like everything else that goes on”.

Both the nurse and the DHB acknowledged a mistake had been made.

Caldwell heard expert evidence from another nurse, who said the drugs should have been immediately drawn into the relevant syringes before they were carried to the unit still in their ampoules. She also raised concerns surrounding labelling.

Caldwell was critical of the decision to place both drugs in the same dish, while noting they had different caps and should have been identifiable regardless. The conduct was labelled a “moderate departure” from the expected standards of care.

Concern was also raised around the failure to clearly identify the woman’s respiratory rate.

The nurse was found to have breached the expected standards of care.

The decision also explored the conduct of Middlemore Hospital after it was heard the unit’s charge nurse had been instructing nurses to collect patients’ medication prior to their arrival, which was a breach of its own policy.

Caldwell was concerned clinical notes were not documented as frequently as they should have been post-overdose.

The DHB said since the incident, drug processes have changed and staff have been provided with further education on administering drugs.

Now Te Whatu Ora Counties Manukau, the DHB was ordered to provide a written apology to the patient, undertake an audit of staff compliance in the dialysis unit, and provide further education to its workers.