狡诈家药物（英语：designer drug），又译为设计师药物、设计毒品、策划药，一种化学药品，其化学结构类似或功能类似于管制物质（Controlled substance），但被特别设计过，以减少其原始药物在药理学上的作用。作出这些设计的主要用意，在于避免在正规的药物测试中，被检查出曾经摄取过管制药物，以逃避管制。作成狡诈家药物的物质中，包括了精神药物，以及增强体物药物（Performance-enhancing drugs）等。

狡诈家药物的发展，可以被视为是药物设计下的一个特定领域。

A designer drug is a structural or functional analog of a controlled substance that has been designed to mimic the pharmacological effects of the original drug, while avoiding classification as illegal and/or detection in standard drug tests. Designer drugs include psychoactive substances that have been designated by the European Union as new psychoactive substances (NPS) as well as analogs of performance-enhancing drugs such as designer steroids. Some of these were originally synthesized by academic or industrial researchers in an effort to discover more potent derivatives with fewer side effects and were later co-opted for illicit use. Other designer drugs were prepared for the first time in clandestine laboratories. Because the efficacy and safety of these substances has not been thoroughly evaluated in animal and human trials, the use of these drugs may result in unexpected side effects.