Evidence map›Paper›PMID 41870531›Full record

ArticlePsychopharmacology2026

Xylazine exacerbates fentanyl-induced respiratory depression and prevents rescue by naloxone in mice.

Joshua M Watkins, Rachel Hahn, Michael Dempsey, Andrea G Hohmann

Abstract read
In one paragraph

Article in Psychopharmacology, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 2 papers.

0numbers the graph read from it
0cells of the map it votes in
2citing papers in PubMed
–field-weighted citation impact
1 · What the graph read from it

What it found

Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.

The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.

2 · The registry

The trial behind it

Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.

Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.

3 · Its place in the literature

Who cites it

2 citing papers in PubMed.

  1. Cannabinoid CBBritish journal of pharmacology · 2026
    Article
  2. Article
4 · The record

Corrections and comments

5 · Who and what money

Authors and funding

4 authors.

Joshua M WatkinsDepartment of Psychological and Brain Sciences, Indiana University, 1101 E. 10th Street, Bloomington, IN, 47405-7007, USA.
Rachel HahnDepartment of Psychological and Brain Sciences, Indiana University, 1101 E. 10th Street, Bloomington, IN, 47405-7007, USA.
Michael DempseyDepartment of Psychological and Brain Sciences, Indiana University, 1101 E. 10th Street, Bloomington, IN, 47405-7007, USA.
Andrea G HohmannDepartment of Psychological and Brain Sciences, Indiana University, 1101 E. 10th Street, Bloomington, IN, 47405-7007, USA. hohmanna@iu.edu.

Funding

Quality Assurance and Quality Control Project Management: Improving Submissions and Study Conduct in the Human Subjects Research Prior Approval ProcessUL1TR002529 · NCATS · INDIANA UNIVERSITY INDIANAPOLIS · PI MOE, SHARON M, WIEHE, SARAH ELIZABETH · 2018 to 2022
$27.2M
Project 3 - In vivo pharmacology of cannabinoid receptor probesP01DA009158 · NIDA · UNIVERSITY OF CONNECTICUT STORRS · PI Alexandros Makriyannis · 1994 to 2026
$26.0M
INTEGRATIVE PREDOCTORAL TRAINING IN DRUG ABUSE RESEARCH AT INDIANA UNIVERSITYT32DA024628 · NIDA · TRUSTEES OF INDIANA UNIVERSITY · PI Andrea Grace Hohmann, Kenneth Mackie · 2008 to 2026
$3.1M
CB2 Cannabinoid Mechanisms for Suppressing Opioid Tolerance and DependenceR01DA047858 · NIDA · TRUSTEES OF INDIANA UNIVERSITY · PI HOHMANN, ANDREA GRACE, MACKIE, KENNETH · 2019 to 2023
$2.6M
Indiana Clinical and Translational Sciences Institute ULTR002529NCATS NIH HHS UL1 TR002529NIDA NIH HHS DA009158NIDA NIH HHS P01 DA009158NIDA NIH HHS R01 DA047858NIDA NIH HHS T32 DA024628Sigma Xi G20240315-9075
6 · The paper itself

Abstract

introductionXylazine is a veterinary sedative and widespread adulterant of illicit opioids, where it is commonly detected in combination with the potent synthetic µ opioid receptor (MOR) agonist fentanyl in fatal overdose.

methodsWe used whole body plethysmography to evaluate the respiratory effects of xylazine in the presence and absence of fentanyl in awake C57BL/6 mice of both sexes. We asked whether suppression of breathing by xylazine-adulterated fentanyl resisted reversal with naloxone. We identified receptor mechanisms necessary to reverse effects of xylazine-adulterated fentanyl on breathing.

resultsXylazine rapidly and dose-dependently suppressed minute ventilation, respiratory frequency, and tidal volume, producing profound respiratory depression at low doses. These effects were dependent on α-2 adrenergic receptors (α2ARs) and were blocked by the α2AR antagonist atipamezole. Xylazine, combined with a dose of fentanyl with modest respiratory effects, suppressed breathing with greater efficacy than when administered alone. A dose of naloxone sufficient to reverse fentanyl-induced respiratory depression was ineffective in reversing the respiratory suppression induced by xylazine-adulterated fentanyl. By contrast, combinations of naloxone with atipamezole rapidly and fully reversed respiratory suppression induced by xylazine-adulterated fentanyl. The same dose of atipamezole, administered alone, produced significant, but markedly delayed reversal.

conclusionXylazine suppresses breathing via activation of α2ARs, an effect enhanced by coadministration with the MOR agonist fentanyl. Respiratory suppression inflicted by the mixture of xylazine and fentanyl resisted reversal by naloxone but was fully reversible by subsequent coadministration of both naloxone and atipamezole.

Indexed as

AdulterantFentanylLethal overdoseOpioid epidemicOverdose reversalRespiratory depressionXylazine

Identifiers

PMID41870531
PMCPMC13035332

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Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.