Nitazenes -- a class of highly potent synthetic opioids -- are rapidly emerging as a major contributor to the overdose crisis, according to a Pain Medicine review published on Sept 14 by authors from Vanderbilt University Medical Center and the University of Pittsburgh Medical Center.

Originally developed in the 1950s but never approved for clinical use, these substances are over 20 times more potent than fentanyl and hundreds to thousands of times more potent than morphine.

They can come in liquid, pills or powder form and have been found in substances sold via social media and on the illicit drug market since 2019.

Created as a potential pain reliever but never approved for medical use in humans or studied in a clinical trial, nitazenes are an illegal Schedule I drug that can be difficult to detect with standard drug tests and are often mixed into counterfeit pills or other street drugs.

"For patients, especially those with opioid use disorder or those exposed to illicit substances, nitazenes pose a serious and often hidden threat," said co-author Shravani Durbhakula, MD, associate professor of Anesthesiology, Division of Pain Medicine at Vanderbilt University Medical Center.

"Because these drugs may not show up on routine toxicology screens, clinicians could miss a critical piece of the diagnosis during overdose treatment. Patients may also need higher or repeated doses of naloxone to reverse their effects," she said.

The Tennessee State Unintentional Drug Overdose Reporting System (TN SUDORS) identified a total of 92 nitazene-involved fatal drug overdoses among Tennessee residents from 2019-2023.

In Tennessee, naloxone was administered in only one in three deaths involving nitazenes, and in all nitazene-involved deaths the drug was laced with other substances, most commonly fentanyl and methamphetamine.

"Many people consuming nitazenes don't even know they're taking them," Durbhakula said. "These substances are often adulterants in pills sold as other opioids, making public education more important than ever.

"We also want to stress that this is not just a drug issue; it is a public health emergency. Addressing it will require collaboration between clinicians, public health officials, law enforcement and community organizations to implement harm-reduction strategies, support addiction treatment, and raise awareness about these evolving threats," she added.

The authors recommend expanding access to new test strips that can detect nitazenes and for at-risk patients to have access to take-home naloxone, addiction treatment and education about counterfeit pills.

"Nitazenes are an emerging class of synthetic opioids that are even more potent than fentanyl and often undetected by routine drug tests," said corresponding author Ryan Mortman, MD, a resident in the Department of Physical Medicine and Rehabilitation at the University of Pittsburgh Medical Center.

"Their rapid spread in the illicit drug market, combined with the difficulty of reversing overdoses, underscores the urgent need for public awareness, early recognition, and expanded access to harm-reduction tools such as naloxone," he said.

Co-authorTrent Emerick, MD, associate professor of Anesthesiology and Perioperative Medicine and Bioengineering at the University of Pittsburgh's School of Medicine, said next steps are to generate human clinical data to better understand nitazenes' effects, especially long-term health impacts, metabolism and response to treatments like naloxone.

"The opioid crisis continues to evolve, and a thorough understanding of the mechanisms and risks of nitazenes is crucial for pain physicians, anesthesiologists and other providers," Emerick said.

Read more …Doctors warn of a stealth opioid 20x more potent than fentanyl

Two healthcare workers get COVID-19 vaccinations on the same day. Both show strong antibody responses initially, but six months later one stays healthy while the other contracts the virus. A new study published in Science Translational Medicine could help explain this difference.

Researchers tracked individuals' antibody levels after vaccinations and identified four distinct patterns of immune response after the first booster vaccination. Notably, the group that started with the highest antibody levels but experienced a faster decline were infected earlier. People with lower blood levels of IgA(S) antibodies, which protect the nose and throat, were also at higher risk. The findings suggest that monitoring how antibody levels change over time could assist in identifying individuals at greater risk of infection.

Led by scientists from Nagoya University in Japan, the research team measured antibody levels in 2,526 people over 18 months to see how vaccine responses changed between the first vaccination and later booster shots. They developed a mathematical classification system for COVID-19 vaccine responses using long-term tracking and AI-based computer analysis, becoming the first to systematically identify and characterize the "rapid-decliner" group.

The researchers found that immune responses fell into four clear patterns: some people maintained high antibody levels over time (durable responders), others started with strong levels but lost them quickly (rapid-decliners), a third group produced few antibodies that also declined rapidly (vulnerable responders), and the rest fell in between (intermediate responders).

Immunity that peaks early and then drops

According to Shingo Iwami, senior author and professor at Nagoya University's Graduate School of Science, the results for the rapid-decliner group were surprising. "In spite of their impressive initial immune response, they caught COVID-19 sooner than other groups, while durable responders maintained protection for longer periods. One-time blood tests for IgG antibodies, the antibody type we used for classification, couldn't detect this risk. Only by tracking changes over months did we see the pattern," he explained.

A breakthrough or subsequent infection refers to infections that occur after vaccination because the virus overcomes the immune protection that vaccines provide. The researchers found that people whose antibodies declined faster, either because they started low or dropped quickly (vulnerable responders and rapid-decliners), were slightly more likely to get breakthrough infections earlier.

After booster vaccinations, 29% of participants fell into the durable responder category, 28% were vulnerable responders, and 19% were rapid-decliners. The remaining participants showed intermediate patterns. The differences in breakthrough infection rates between groups were modest -- 5.2% for durable responders and 6% for vulnerable and rapid-decliners.

Breakthrough infections linked to IgA(S) antibody levels

The study also revealed that participants who experienced breakthrough infections had lower levels of IgA(S) antibodies in their blood several weeks after vaccination. These antibodies protect the nose and throat and are our first line of defense against respiratory viruses.

Importantly, the researchers found a strong correlation between blood IgA(S) levels and nasal IgA(S) levels, suggesting that blood tests can reliably indicate the strength of immune protection in airways. As a result, measuring blood IgA(S) levels after vaccination may help identify individuals at higher risk for breakthrough infection, especially among vulnerable groups.

While these results provide a foundation for future research, Professor Iwami emphasized the importance of identifying the underlying biological mechanisms responsible for the rapid decline in antibody levels in order to develop more effective vaccination strategies. Previous research points to factors such as age, genetic variation, vaccine-specific characteristics, and environmental influences, including sleep habits, stress levels, and medications being taken at the same time.

"This is the first time we've been able to clearly group how people respond to COVID-19 vaccines," Professor Iwami noted. "Identifying the rapid-decliner pattern is especially important -- it helps explain why some people may need boosters sooner than others. This could potentially contribute to better, more personalized vaccination strategies. However, whether antibody testing can be used widely depends on cost, accuracy, and if the benefits are worthwhile compared to current strategies. More research is needed to understand its full potential."

Read more …The hidden group that loses COVID protection fast

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