The Drug in ‘Tranq Dope’ Is Great for Horses but Horrific for Humans
Xylazine is being mixed with fentanyl by drug dealers, causing deadly results. Controlling it is tricky.

Penny, a sorrel mare aged 3 with a white blaze was slobbering and biting at her feed, which were signs of an underlying toothache. A dental exam revealed that Penny needed to have two wolf-teeth extracted, and some of the sharp edges on her molars were ground down. This required that her jaws be propped open using a speculum.
Boyd Spratling gave Penny a shot of the common tranquilizer xylazine to protect her from pain and from a horse that was ten times heavier than him. In a matter of moments, Penny's long neck began to droop and her eyelids started to flutter at half-mast. Penny left the rural Nevada clinic 45 minutes after her dental surgery was completed. She then walked into her trailer.