Xylazine HCl

What is this medication for?

• Sedation/restraint/analgesia; pre-anesthesia before ketamine (field anesthesia); epidural
• Standing restraint/analgesia (extreme sensitivity — dose discipline); local-procedure drowsiness
• Sedation/analgesic/premed (largely displaced by dexmedetomidine); emetic in cats (reliable at label doses)

How is it given?

Give exactly as your veterinarian prescribed — never change the dose or stop on your own unless your veterinarian has told you to.

What if I miss a dose?

• Give it as soon as you remember — unless it is almost time for the next dose (then skip the missed one; never double up).
• Call your clinic if you miss more than one dose in a row.

Side effects — what should I watch for?

Effects listed as common in this handout

• Horses may kick after auditory stimulus despite drowsiness (The classic warning sign)
• Sweating, ↑ICP (Additional)
• Emesis (then drowsiness) (Expected sequence)

Worth a phone call to your veterinarian

• Bradycardia + partial AV block, respiratory ↓, muscle tremors (Expected physiology — monitor)

⚠️ Contact your veterinarian or an emergency clinic IMMEDIATELY if you notice

• Bloat from aerophagia (dogs), increased urination (Species notes)
• Ruminant collapse at overdose (Dose-discipline consequence)

Before starting (or refilling), tell your veterinarian if your pet:

• has or has had: Epinephrine co-use/active ventricular arrhythmias; debilitated/dehydrated ruminants; UT obstruction; last-trimester cattle
• has or has had: Cardiac dysfunction, low blood pressure/shock, respiratory disease, severe hepatic/renal, seizures; intestinal-impaction patients; laminitis vasoconstrictive phase

• is pregnant, nursing, or used for breeding
• is taking any other medications, supplements, or flea/tick products, including:
  • Epinephrine
  • Ketamine
  • Butorphanol/opioids
  • Yohimbine/tolazoline/atipamezole

Storage and handling

Standard injection storage; never intra-arterial (seizures/collapse).

Good to know

• The order IS the safety: xylazine → deep drowsiness → ketamine; skipping the wait invites rigidity/seizures (see ketamine.md horse row).
• Cattle sensitivity scale: what sedates a horse deeply can drop a cow — ruminant doses are fractions of equine.
• The kick warning: a "sleeping" horse is a hearing-intact horse — auditory startle → kick without warning.
• Cat-emetic property doubles as a toxicology tool (pre-activated-charcoal induction) where apomorphine is dog-only.