A case series of accidental xylazine intoxication in humans; Is there a role of naloxone as an antidote?

Xylazine is a type of sedative commonly used in veterinary medicine. It acts on the central alpha-2 receptor and suppresses norepinephrine release from the peripheral nerve terminal. It is also reported to have action on cholinergic, serotogenic, H2-histamine, dopaminergic, and opioid receptors. Once administered in animals, it causes hypotension, bradycardia, central nervous system depression, and respiratory depression. The effect will start within minutes after absorption and last up to 4 h depending on the dosage given. Till date, it is only exclusively used in animals as approved by the Food and Drug Administration. Human intoxication is uncommon, and no specific antidote is available. Naloxone, a competitive opioid receptor antagonist, was postulated to have an antidotal effect on xylazine. We report two cases of accidental human injection with xylazine. Naloxone was administered in one of the cases. Acute hypertension and mydriasis were observed; however, no apparent reversal of toxidrome was seen. This finding reveals the question regarding the efficacy and benefit of naloxone usage in xylazine intoxication. General management remains supportive of care focusing on ventilation and hemodynamics. Attending physicians should be aware of potential xylazine intoxication incidents in the area of livestock or veterinary activities.