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Xylazine effects on opioid-induced brain hypoxia
Shinbe Choi1, Matthew R Irwin1, Eugene A Kiyatkin2
1Behavioral Neuroscience Branch, National Institute On Drug Abuse Intramural Research Program, National Institutes of Health, DHHS, Baltimore, MD, 21224, USA.
Psychopharmacology
|June 20, 2023
Summary
Xylazine worsens opioid overdose by causing prolonged brain hypoxia. This study in rats shows xylazine (XLZ) combined with fentanyl or heroin significantly impairs the brain's ability to recover oxygen levels.
Area of Science:
- Neuroscience
- Toxicology
- Pharmacology
Background:
- Xylazine is an increasingly common adulterant in fatal opioid overdoses.
- Xylazine is known to depress vital functions, including respiration and circulation.
- The precise role of xylazine in opioid-induced deaths remains unclear.
Purpose of the Study:
- To investigate the brain-specific effects of xylazine on hypothermia and hypoxia.
- To examine the combined effects of xylazine with fentanyl and heroin on brain oxygen levels.
Main Methods:
- Experiments were conducted using freely moving rats.
- Intravenous xylazine, fentanyl, and heroin were administered at human-relevant doses.
- Brain and body temperature, locomotor activity, and nucleus accumbens oxygenation were measured.
Main Results:
- Xylazine caused dose-dependent decreases in activity and prolonged hypothermia.
- Xylazine reduced nucleus accumbens oxygenation, indicating brain hypoxia.
- Mixtures of xylazine with fentanyl or heroin exacerbated brain hypoxia and impaired compensatory mechanisms.
Conclusions:
- Xylazine potentiates the life-threatening effects of opioids.
- Worsened brain hypoxia is a key mechanism contributing to xylazine-positive opioid overdose deaths.
- Findings highlight the critical danger of xylazine as an opioid adulterant.
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