• Emerging drugs, which include designer drugs and new psychoactive substances, are substances that have appeared or become more popular in the drug market in recent years.
• Emerging drugs have unpredictable health effects. They may be as powerful or more powerful than existing drugs, and may be fatal.
• Because drug markets change quickly, NIDA supports the National Drug Early Warning System (NDEWS), which tracks emerging substances. NIDA also advances the science on emerging drugs by supporting research on their use and on their health effects.

Source: https://nida.nih.gov/research-topics/emerging-drug-trends