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State of California—Health and Human Services Agency
California Department of Public Health

AFL 23-35
November 28, 2023

All Facilities

Xylazine in the Illicit Drug Supply and Patient Best Practices

​All Facilities Letter (AFL) Summary

This AFL notifies all facilities of the veterinary sedative xylazine emerging in the United States (U.S.) illicit drug supply, predominantly with fentanyl use. Despite its low presence in California, levels could increase. Facilities should be prepared to support patients who have been exposed to xylazine.​

​On April 12, 2023, the Biden-Harris Administration designated fentanyl adulterated or associated with xylazine as an emerging threat to the U.S. Xylazine is an FDA approved veterinary sedative but is not approved for use in humans. Xylazine can be found in the U.S. illicit drug supply, where it is known on the street as “tranq" or “tranq dope". Xylazine is increasingly present in overdose deaths, compounding the overdose crisis. It is almost exclusively being added to fentanyl, thus people who use fentanyl may be exposed.​

Although xylazine is present in California, it does not appear to have penetrated California's illicit drug supply to the extent it has in the northeastern U.S. However, experts are concerned that the presence of illicit xylazine could increase in California.

Informing Clinicians of Suspected Xylazine Exposure

Health facilities should inform clinicians to suspect xylazine exposure when:

  • The patient continues to have opioid-like effects following administration of an opioid antagonist. While opioid antagonists are expected to reverse the effects of a current opioid overdose, the effects of xylazine may persist.
  • The patient presents with concomitant hypotension and bradycardia or cardiac conduction disturbances in the setting of drug use.
    • Of note, xylazine is an alpha-2 adrenergic receptor agonist with a mode of action similar to clonidine, guanfacine, and dexmedetomidine; and with some structural similarity to phenothiazines.
  • The patient presents with necrotic skin ulcerations in the setting of concomitant substance use disorder, especially opioid use disorder.

Clinical Management of Patients with Xylazine Exposure

Clinical management may involve, but is not limited to:

  • Supportive care related to bradycardia, hypotension, respiratory depression
  • Oxygenation, ventilatory support, and vasopressor support
  • Withdrawal management (Note: The FDA has not approved a medication for xylazine withdrawal, the California Department of Public Health (CDPH) recommends clinicians refer to the Philadelphia Department of Public Health, Penn Medicine's Center for Addiction Medicine, and CDPH for best practice approaches)
  • Xylazine-associated wound care (refer to “Xylazine-Associated Wounds and Wound Care")
  • Call the California Poison Control System at 1-800-222-1222 for real-time clinical advice for patient care related to any suspected toxic exposure.

Xylazine-Associated Wounds and Wound Care

Frequent xylazine use is associated with a higher prevalence of skin problems, including abscesses, ulcers, and infections. Severe infections and necrotic skin ulcerations among people who repeatedly use xylazine can appear, and for people who inject it, the wounds may appear beyond the site of injection.

Patients who are ready to seek treatment for substance use disorder might be turned away from residential treatment if those facilities do not have the capacity to manage xylazine-associated wounds. ​

Treatment of wounds should occur as early as possible to avoid further complications, which includes:

  • Cleaning wounds with soap and clean water
  • Keeping the wound bed moist
  • Antibiotic use if bacterial infection is present

Addressing Fentanyl and Opioid Use Disorder

Xylazine is almost exclusively combined with fentanyl. CDPH recommends that all healthcare providers provide optimal patient follow-up care after fentanyl-positive urine screen, which may include:

  • Providing take-home naloxone
  • Offering a prescription of buprenorphine (which no longer requires an X waiver) or other medication for opioid use disorder (MOUD)
  • Referral for MOUD treatment
  • Connecting the patient with a peer navigator for immediate engagement and to provide resources, information, and support for opioid use disorder
  • Following up with the patient after they leave the hospital/emergency department to discuss treatment progress and offer further support.

For questions or additional information, contact the CDPH Overdose Prevention Initiative ( or visit CDPH's Xylazine Website



Original signed by Cassie Dunham

Cassie Dunham

Deputy Director



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