How does rompun effect humans if accidentally injected?

I have worked with Rompun (Xylizine) for years in animal control applications as a Sheriff's Deputy under a vet's supervision. I have used it on dogs and cattle, mostly bulls and steers. Every time the vets resupply me they remind me to be very careful with it as it will kill people in very small doses! It even effects different species of animals very differently. The dose I use on a 1500 lb bull also works on a 150 lb dog and would kill anyone accidentally darted DEAD.