Mechanism of action: Xylazine balliculeVisual mnemonic: Xylazine mascot “Xyla Tranq” Known as “Tranq”, cut with fentanyl Xyla the Horse → horse tranquilizer Orange plus signs → α2 agonist
What it isAlpha-2 agonist veterinary sedative; a common adulterant of illicit fentanyl.
Why this oneIts recognition matters because it explains sedation that naloxone does not reverse.
What limits it⚑ Naloxone does NOT reverse it, and it causes severe necrotic ulcers at and away from injection sites. No approved human use.
Molecular structure: Xylazine
FDA-approved for
veterinary sedation (not human-approved)
Off-label
veterinary sedation (now a common adulterant in the illicit fentanyl supply)
NO BOXED WARNINGS
Principal risk⚑ Naloxone does NOT reverse it, and it causes severe necrotic ulcers at and away from injection