This narrative review seeks to delve into the different on and off-label medications commonly used with intrathecal drug delivery systems (IDDS) and their clinical applications specifically in pain management settings. This review utilizes a variety of studies including reviews, retrospective chart analyses, and more to analyze the current effectiveness of various pharmacological agents on reducing chronic pain through IDDS. The initial results of intrathecal delivery of these medications have provided benefit in pain reduction and overall patient satisfaction; however, this review will seek to analyze the current data and understanding and suggest areas of strength and improvement within the field and our current understanding.