Such was the hold that the potent opioid patches had over her, Daley, 35, a woman with a complicated medical history but no prior criminal record, could see no other option. Offered money by the pharmacist, Daley wanted only prescription drugs.

And then, after being charged and granted bail, and after the reality of what she had done had set in, leaving her shocked, ashamed and remorseful, Daley did it again. Three weeks after her first armed robbery, Daley walked into a pharmacy at New Lambton, pressed a blade against the neck of a female stuff member and yelled: "I want fentanyl patches".

The case highlights the extremely addictive nature of the powerful prescription painkiller fentanyl, which is about 80 to 100 times stronger than morphine, against the backdrop of an overall surge in prescription drug addiction and death during Australia's ballooning opioid crisis.

On Friday in Newcastle District Court, Daley was jailed for a maximum of three years, with a non-parole period of 20 weeks, or time served, a significant reduction on her sentence due to Daley's numerous physical and mental health issues and the severe fentanyl addiction she was suffering at the time of the robberies.

Judge Roy Ellis said Daley's five months behind bars had been a "horrendous experience" and she had been hospitalised four times, including one occasion where she was "clinically dead" and had to be revived by another inmate. Daley, through her solicitor Chris O'Brien, provided a statement to the Newcastle Herald, outlining her shame and commitment to remain fentanyl free.

"I would never, ever again take opioid pain based medication outside a hospital (which was previously prescribed) and it will never be fentanyl under any circumstances," Daley said in a statement provided by Mr O'Brien. "I am so ashamed that this has happened."

Fentanyl is prescribed to help treat acute or chronic pain, but is often used as a recreational drug and mixed with heroin or cocaine.

In the United States, fentanyl has been blamed for the accidental overdose deaths of musicians Prince, Tom Petty and Mac Miller among others, and in 2018 was used for the first time in the lethal injection of an inmate on death row in Nebraska.

Daley, of Stockton, did not have a previous drug addiction and was prescribed fentanyl to manage the pain of acute pancreatitis and a back injury.

But she did not realise how dependent she had become until her addiction was out of control. "She went straight from the doctor's surgery, having been refused fentanyl," Judge Ellis said on Friday. "Picked up a knife and then committed the first offence. It seemed that she could think of no other way to manage her situation."

It was about 3pm on April 16 when Daley walked into the Blooms Pharmacy at Mayfield armed with a large knife. She grabbed a staff member and the pair struggled as Daley tried to put the knife up to her throat and face. "I'll give you whatever you want, just don't hurt her," a pharmacist told Daley. "Do you want money or drugs?" Daley replied: "Drugs."

And when asked if she wanted Valium, Daley replied "Durogesic", a brand name for the fentanyl patches.

The pharmacist handed over four boxes of the strongest fentanyl patches and Daley fled the store.

The victim suffered a cut to her hand but, after she had calmed down, was able to identify Daley as a customer who had been prescribed fentanyl in the past.

Daley was arrested the next day and charged with armed robbery but police granted her conditional bail.

Then on May 4, Daley walked into Strachans Day Night Pharmacy at New Lambton and pressed a knife blade against a staff member's neck. "I want fentanyl patches, I want fentanyl patches," Daley yelled.

She asked for the strongest patches, but staff gave her one box of the weakest version of the drug and she left.

After the second armed robbery, Daley spent five weeks behind bars, during which she was hospitalised four times, including one occasion where another inmate had to revive her.