Sustained-release refers to a method of delivering medication that allows it to be released into the body gradually over an extended period. This approach helps maintain consistent drug levels in the bloodstream, reducing the need for frequent dosing. It is commonly used in various medications, including pain relievers and antidepressants. The design of sustained-release formulations often involves special coatings or matrix systems that control the rate at which the drug is released. This can improve patient compliance and minimize side effects, making it a valuable option in pharmacotherapy for conditions like chronic pain or depression.