Emerging Drugs: What We Currently Know

Current situation

A rapidly changing drug supply

The illegal drug market is shifting toward synthetic, mixed, and rapidly changing substances that are harder to detect and treat.123 Fentanyl still dominates — but is no longer the most potent substance.145 Changes in drug potency, combined with the increasingly unpredictable content of illegal drug products, can be lethal and make it harder to predict, prevent, and reverse drug overdoses.67

Since 2013, the United Nations Office on Drugs and Crime has identified more than 1,500 emerging drugs worldwide.3 They may be sold in a variety of places, including illegal drug markets, gas stations, convenience stores, or online.89 Some substances were developed as potential medical treatments or research chemicals, while others come from illegal labs and are created to mimic the effects of substances regulated under the Controlled Substances Act.10 These substances can be added to other drugs without a person's knowledge, making every use unpredictable.

Detecting and identifying emerging drugs quickly is a critical challenge. Because these substances are new to the illegal drug market, clinicians, public health practitioners, and researchers may not know their effects or potency until people begin presenting to emergency departments with serious symptoms.

CDC response

CDC and federal partners continue to monitor emerging drug threats to better understand drug use and overdose trends. Current CDC response activities include:

• Conducting epidemiological analyses to understand geographic spread, population risk, and overdose trends linked to specific emerging substances.
• Coordinating with state and local health departments to strengthen toxicology testing and reporting for new, emerging drug threats detected in the drug supply.
• Supporting drug checking programs and laboratory networks that can rapidly identify new compounds.
• Issuing Health Alert Network (HAN) advisories to notify clinicians, public health officials, and emergency responders about newly identified substances.
• Developing clinical guidance for healthcare providers on detection and management of overdoses involving emerging drugs, including those that do not respond to naloxone.
• Collaborating with the White House Office of National Drug Control Policy (ONDCP), Drug Enforcement Agency (DEA), Food and Drug Administration (FDA), Substance Abuse and Mental Health Services Administration (SAMHSA), and other federal agencies on surveillance, emergency scheduling, and coordinated response.

What you should do

Whether you are a member of the public, a healthcare provider, or a community organization, there are steps you can take to stay informed and help protect yourself and others:

• Learn the signs of an opioid overdose and what steps to take.
• Carry an opioid overdose reversal medication (OORM).

Emerging drug situation summaries

To learn more about specific emerging substances, select a substance below to read the full situation summary, including clinical guidance, surveillance data, and recommendations.

Medetomidine Situation Summary

Medetomidine is found in the US illegal drug supply, primarily mixed with illegally made fentanyl.

Carfentanil Situation Summary

Carfentanil is a synthetic opioid that can cause an overdose even in small amounts.

Xylazine

Xylazine is a non-opioid sedative or tranquilizer. Xylazine is not approved for use in people.

Resources

National Drug Early Warning System (NDEWS)

2025 National Drug Threat Assessment

2026 National Drug Control Strategy Released – The White House

Medetomidine in the U.S. Illegal Fentanyl Supply Increasing Risk for Overdose and Severe Withdrawal Syndrome

About Overdose Data to Action