Metro police have arrested a man for robbing a Donelson Walgreens at gunpoint early Tuesday morning.The robbery happened around 2 a.m. at the store on Donelson Pike at Elm Hill Pike.Authorities said Cody Unger approached the pharmacy's counter and spoke with the pharmacist for a short period of time. The pharmacist reported Unger had been in the store the night before to fill a prescription for hydrocodone. Unger then produced a handgun and demanded additional hydrocodone and oxycodone. He received 700 prescription pills before he fled the scene. Police have since recovered the handgun, a .22 revolver. Unger was taken into custody a short time later. No one was injured during the incident.He is charged with aggravated robbery and remains jailed in lieu of a $50,000.