“Human Adverse Reaction” means a noxious and unintended reaction that occurs in a human being following exposure to veterinary medicine. Xylazine (also known as ‘Tranq’) is a powerful sedative that the US FDA has approved for veterinary use.  Xylazine is used for sedation, anaesthesia, muscle relaxation, and analgesia in horses, cattle, and other non-human mammals. It is also referred to as the Zombie drug.

Fentanyl is a synthetic opioid 50 to 100 times more potent than morphine. It is strictly a prescription product which is primarily used in pain management. Fentanyl may also be illicitly manufactured and distributed through illicit drug markets. Fentanyl may be added to other drugs, especially opioids, because of its extreme potency. This makes drugs cheaper, more potent, addictive, and dangerous.

Xylazine has been identified as a contaminant in combination with opioids, such as illicit fentanyl and other illicit drugs, to lengthen their euphoric effects. However, Xylazine and fentanyl drug mixtures place users at a higher risk of fatal drug poisoning. People who inject drug mixtures containing xylazine are at risk of developing tissue necrosis, which may lead to amputation. The FDA has alerted healthcare professionals of risks to patients exposed to xylazine in illicit drugs. Besides, the FDA issued a letter to stakeholders providing clinical information about the dangers of severe, necrotic skin ulcerations from repeated xylazine exposure, possible withdrawal symptoms, and xylazine’s interference with successful treatment of opioid overdoses.

The reaction caused by the illicit combination of Xylazine with opioids would qualify to be referred to as a “Human Adverse Reaction”. Naloxone is a drug that can reverse the effects of opioids. However, as Xylazine is not an opioid, the situation can be challenging. However, naloxone can counteract the opioid component of the combination.

Xylazine may be illicitly produced or diverted from the animal drug supply. It is essential to identify the source of Xylazine, as it is strictly a prescription product for veterinary use. If it is diverted from the animal drug supply then the side effect would qualify as a “Human Adverse Reaction”.