Which of the following are the three classes of designer drugs?

The correct answer identifies three classes of designer drugs that are specifically related to the modifications made to existing substances to enhance certain effects or evade legal restrictions. In this context, fentanyl analogs represent a class of synthetic opioids designed to be more potent than traditional opioids. Meperidine analogs relate to modifications of a well-known opioid pain medication, reflecting how existing drugs can be altered to create new psychoactive substances. MDMA, while originally established, also has various analogs that are created by altering its chemical structure, leading to different effects and potentials for abuse.

This classification demonstrates how drug manufacturers may create new versions of existing drugs to mimic their effects while attempting to circumvent regulations, which is a primary concern in drug enforcement and public health. Understanding these categories is essential for crime scene analysts and forensic professionals who may encounter such substances in various contexts.