you die

Xylazine, an alpha-2 agonist, may be reversed using yohimbine. However, it is not reversed every time it is used. Xylazine (also known by the trade name Rompun) frequently wears off quickly enough that reversal is not needed. This would particularly be true if used as an anesthesia pre-medication prior to propofol or thiopental induction. If xylazine is used as the sole anesthestic induction agent, the duration of the procedure would dictate whether or not yohimbine would be necessary. Yohimbine can also be used to reverse xylazine if a patient's heart rate or blood pressure goes down while under anesthesia and a faster recovery is desired. Combining xylazine with an anticholinergic like glycopyrrolate would help prevent the bradycardia associated with xylazine.

Only in the sense that both of them are illegal drugs in the US (Xylazine is approved for veterinary use, but not for human use). The two are not at all similar in structure or mechanism.

No problem if medications are used on healthy horses at the correct dosage for their route Vet schools and "books" will recommend against using "ace" stating it can cause "priapism" in males. Never seen it in 40 years of practice, nor have I heard of any other vet who's had it be a problem It's a good combination, especially if you can't afford detomidine and need a sedative to act longer than the xylazine alone