Jeffrey Treacy, 41, of Kyabram, was sent to prison for four years, with a non-parole period of two years for armed robbery and a series of other burglaries and thefts.

The Bendigo County Court heard Treacy threatened a pharmacist and a pharmacy student who was on placement at Echuca's Weller and Barlow pharmacy on April 17 last year.

Treacy entered the pharmacy with a shotgun and demanded boxes of painkillers OxyContin and MScontin.

The court heard the pharmacist on duty did not believe Treacy was serious in his request until Treacy produced the firearm from his bag.

Treacy fled after filling his bag with the drugs and discarded the gun, which was unloaded.

He was arrested on April 25 and made full admissions to the armed robbery.

According to a police interview Treacy said the reason for the robbery was that he had chronic pain and had exhausted his supply of painkillers at home.

The court heard Treacy was also guilty of stealing painkillers during a break-in at Ian Collie Pharmacy in Kyabram on July 6, 2012.

Treacy used a claw hammer to smash in the rear doors of the pharmacy in order to steal about $500 worth of painkillers. The broken glass triggered the security alarm and Treacy was arrested on scene.

Judge Irene Lawson said in the sentencing on Thursday that Treacy showed a concerning pattern of behaviour.

"This is serious, pre-meditated offending," she said.

The court was told staff from Weller and Barlow pharmacy have sought counselling since the robbery.

A victim impact statement from the 21-year-old pharmacy student said she was unable to finish her placement due to the trauma.

"She has doubts about her safety in her workplace," Judge Lawson said. "It's not something she will ever forget."

The court heard Treacy has an extensive criminal history including prior convictions for burglary.

A doctors report read to the court noted Treacy suffered a spinal injury as a consequence of kick boxing in 1999. He has been prescribed painkillers, including MScontin, and has been using Xanax twice a day.