Gainesville law enforcement and medical professionals are warning the community of a new and deadlier synthetic opioid drug on the streets identified as Isotonitazene, or ISO.  

ISO is estimated to be 20 to 200 times stronger than fentanyl, another synthetic opioid that is already 50 times stronger than heroin, 100 times stronger than morphine, and is the leading cause of death for Americans ages 18 to 45. 

Dr. Kent Mathias is an assistant professor of psychiatry and addiction at the University of Florida and runs the dual diagnosis unit at the UF Health Psychiatric Hospital. He said that instead of ISO’s danger driving people away from using the drug, they’re attracted more. 

“There’s this weird phenomenon in the drug world where people see things that are really strong, and say, ‘I want some,’ because maybe it lasts longer,” Mathias said. “They can get one and spread it out. But that’s how overdoses happen because people don’t realize how strong it is.” 

ISO comes from a group of opioid drugs known as nitazines that were originally developed in the 1950s for pain relief. The FDA never approved the drugs for medical use because of their high potency, and classified them as illegal Schedule I drugs.  

The beginning of ISO’s presence traces back to Europe in 2019 before it began showing up in seized drug samples and toxicology reports in Canada and the United States later that year. Medical Discovery News estimates ISO may have killed up to 2,000 people since 2019. 

In 2022, Florida Attorney General Ashley Moody made a video warning Floridians that the new drug had reached their state, saying, “ISO, is so strong that it can kill just by coming in contact with someone’s skin or being accidentally inhaled. ISO has already been linked to overdose deaths in Florida, so please, never take any illicit drug and know that using just one time could cost you your life.” 

Police arrested a man with 20 kilograms of ISO in West Palm Beach earlier this summer, and Marion County has already reported an ISO overdose death. The Florida Medical Examiners Commission reported that overdose deaths in Alachua County increased nearly 30% from 2019 to 2021 and reached over 100 deaths in 2023. 

Mathias explained that chemists in the billion-dollar drug business creating new and cheaper synthetics like ISO creates a hurdle for law enforcement because tests aren’t programmed to detect the substances yet. Drug dealers also intentionally mislabel products in order to fly under law enforcement’s testing radars.  

While diagnosis reports in Gainesville would indicate an outbreak of the stimulant drug Ecstasy, also known as MDMA or Molly, Mathias said these numbers are false. Drug dealers are labeling bath salts as Molly instead because they go undetected in urine and blood testing, unlike actual Ecstasy. 

Dealers will also lace less potent drugs or counterfeit oxycodone pills with drugs like ISO without users realizing it. 

“Most overdose deaths happen from people that are chronic users. However, your risk of overdose death is actually the highest when you are a naive user because people don’t know how strong the stuff is,” Mathias said. “With something like ISO, it’s so strong that the one-time use for even the chronic user could be it.” 

A drug’s duration of action, and how long it’s effective, is critical for developing opioid overdose reversal medications such as the over-the-counter nasal spray Narcan. Fentanyl’s duration of action is about 30 to 60 minutes, while ISO’s is between four and six hours. Narcan only lasts about 60 to 90 minutes.  

“Once [Narcan] wears off, if you still have ISO on board, you’ll stop breathing again,” Mathias said. “My rule of thumb is, if you’re not breathing, you can’t really hurt someone more. You should just keep giving Narcan.” 

But ISO’s affinity, or how strongly it binds to pain receptors in the brain, also makes it much harder for Narcan to have any effect. 

Less potent drugs have more room inside pain receptors, which allows a reversal agent such as Narcan to slide past the drug to push it out. But ISO sits so tightly inside receptors that Narcan can’t do that as well.

Opvee is another nasal spray with a longer duration of action developed by pharmaceutical companies in response to stronger synthetics like ISO. Mathias said harm reduction measures such as increased access to opioid reversals can be helpful, considering that if someone is already addicted and not getting treatment, their likelihood of continued drug use is very high. 

But he also said combatting substance abuse needs to start with efforts on the front end of addiction.  

Gainesville offers the UF Health Psychiatric Hospital, open 24 hours a day, for free inpatient care evaluations; Meridian Behavioral Healthcare walk-in clinics; Alachua Methadone Clinics; and the UF Health Florida Recovery Center, voted No. 1  in Florida and No. 5 in the nation for rehab. 

As the problem of more sick people than resources available continues in an increasingly isolated post-pandemic population, Mathias said what is available can always be improved. 

“Addiction has been around since man has been around,” he said. “I think with more education, more community support, more understanding of addiction really being a disease and not a moral failing or a choice, it can help. Where there’s breath, there’s hope.”