Isotonitazene, often referred to by the street name “ISO,” is a potent, illicit synthetic opioid that has emerged as a significant public health concern. This substance belongs to a class of compounds known as nitazenes, which are structurally distinct from other well-known synthetic opioids like fentanyl. Its presence in the unregulated drug supply has been linked to severe adverse health effects, including a rising number of overdose fatalities. Understanding the characteristics and dangers of isotonitazene is important for individuals and communities to navigate the evolving landscape of synthetic drug threats.
What Is Isotonitazene?
Isotonitazene is a synthetic opioid analgesic developed in the mid-1950s for pain relief. It was never approved for medical use and remained largely unknown until its appearance on the illicit drug market in 2019. It is a member of the nitazene class of opioids, which are benzimidazole derivatives.
This compound is often encountered in powder form, which can appear yellow, brown, or off-white. It has also been found pressed into counterfeit pills, sometimes masquerading as pharmaceutical medications like Dilaudid or oxycodone, or mixed with other illicit substances such as heroin and fentanyl. It is also known as “ISO” or “nitazene.”
Effects and Dangers of Isotonitazene
Isotonitazene exerts its effects by binding to opioid receptors in the brain and spinal cord, similar to other opioids like morphine and fentanyl. This interaction can produce feelings of euphoria, relaxation, and pain relief. Its extreme potency poses a danger, as even very small amounts can lead to severe physiological effects.
The most concerning effect of isotonitazene is respiratory depression, where breathing becomes dangerously slow or stops entirely. This can quickly progress to respiratory arrest and death. Isotonitazene is significantly more potent than morphine, and its potency can be comparable to or even greater than fentanyl. Other effects can include sedation, constricted pupils, decreased heart rate and blood pressure, dizziness, drowsiness, confusion, and nausea. The risk of overdose is further amplified when isotonitazene is unknowingly mixed with other central nervous system depressants, such as benzodiazepines or alcohol.
Recognizing and Responding to Overdose
Recognizing the signs of an opioid overdose is important for immediate intervention. Symptoms commonly associated with an isotonitazene overdose include pinpoint pupils, shallow or stopped breathing, unresponsiveness, loss of consciousness, and pale, blue, or clammy skin. Other indicators may include gurgling sounds, a limp body, or vomiting.
Immediate action is necessary if an overdose is suspected. Calling emergency services is the first and most important step. Naloxone, often known by the brand name Narcan, is an opioid antagonist medication that can temporarily reverse the effects of an opioid overdose. Naloxone works by competitively binding to the mu-opioid receptors in the brain, displacing the opioid and rapidly restoring normal breathing. Because naloxone’s duration of action is generally shorter than potent opioids like isotonitazene, multiple doses may be necessary, and medical professionals should always be involved even after administration.
Legal Status and Broader Concerns
In the United States, isotonitazene has been permanently placed in Schedule I of the Controlled Substances Act (CSA). This classification signifies that the substance has a high potential for abuse, no currently accepted medical use in treatment, and a lack of accepted safety for use under medical supervision. The Drug Enforcement Administration (DEA) temporarily scheduled it in August 2020, with permanent placement becoming effective in December 2021.
The presence of isotonitazene in the illicit drug supply poses significant public health challenges. It is often sourced from countries like China and then mixed into other drugs, making its detection difficult for users. The unpredictable purity and concentration of illegally obtained isotonitazene contribute to the high risk of accidental overdose. The continued emergence of new synthetic opioids like isotonitazene further complicates efforts to control the opioid crisis and underscores the need for ongoing surveillance and public awareness.