Xylazine is an alpha2-adrenergic agonist providing sedation, muscle relaxation and a shorter period of analgesia. It is used for restraint, standing procedures and balanced anesthesia in several veterinary species. Ruminants are particularly sensitive to its pharmacologic effects. A separate small-animal application is induction of emesis in selected cats.
Xylazine stimulates central alpha2-adrenoceptors, reducing norepinephrine release and activity in arousal pathways. Alpha2 effects in the spinal cord and other pain pathways reduce nociceptive transmission, while central actions promote muscle relaxation. These effects produce sedation and analgesia without complete general anesthesia. Stimulation of alpha2-sensitive emetic pathways can also trigger vomiting in cats.
Older label range often considered high; titrate conservatively.
Preanesthetic sedation
0.2–1 mg/kg
IV, IM, SC
Once
Analgesia alternative
0.1–1 mg/kg
IV, IM, SC
Postoperative anxiety
0.1–0.5 mg/kg
IV, IM, SC
Epidural analgesia
0.02–0.25 mg/kg
EPIDURAL
Dilute with sterile saline to 0.26 mL/kg total injection; onset 20-30 minutes and duration 2-5 hours. Exact sterile preparation/excipients must suit epidural use.
Cats
Use / stage
Dose
Route
Schedule
Instructions
Short-term pain
0.1–0.5 mg/kg
IM, IV, SC
Sedation
1.1 mg/kg
IM, IV
Once
Emesis
0.4–0.5 mg/kg
IM, IV
Once
Sedation label alternative
1.1–2.2 mg/kg
IM, SC
Once
Older label range often considered high; titrate conservatively.
Preanesthetic sedation
0.2–1 mg/kg
IV, IM, SC
Once
Analgesia alternative
0.1–1 mg/kg
IV, IM, SC
Postoperative anxiety
0.1–0.5 mg/kg
IV, IM, SC
Emesis
0.44 mg/kg
IM
Once
Horses
Use / stage
Dose
Route
Schedule
Instructions
Sedation
1–2 mg/kg
IM
Once
Standing restraint
0.5–1 mg/kg
IV, IO
Once
Sedative infusion — Loading
0.5–1.1 mg/kg
IV
Once
Sedative infusion — Maintenance
0.72–1 mg/kg/hour
IV
Continuous
Reported regimen describes infusions up to 6 hours.
Colic pain
0.3–0.5 mg/kg
IV
Triple-drip anesthesia
Reference only
IV
500 mg xylazine plus 2 g ketamine in 1 L 5% guaifenesin in dextrose: induction 1.1 mL/kg then 2-4 mL/kg/hour. Recovery about 25-30 minutes; reported mentions yohimbine 0.125 mg/kg for faster recovery without stating reversal route for this regimen. Preserve the combined fluid protocol.
Colic pain
0.2–0.5 mg/kg
IV
Colic pain
0.6–1 mg/kg
IM
Sedation and analgesia
0.2–1.1 mg/kg
IV, IM
Caudal epidural analgesia
0.03–0.35 mg/kg
EPIDURAL
First coccygeal space; perineal sweating common, reported duration 3-5 hours.
Lumbosacral catheter analgesia
0.2 mg/kg
EPIDURAL
Pigs
Use / stage
Dose
Route
Schedule
Instructions
Sedation
0.5–3 mg/kg
IM
Once
Unreliable alone; reported example combines xylazine 2 mg/kg with ketamine 10 mg/kg.
Cattle
Use / stage
Dose
Route
Schedule
Instructions
Sedation
0.1–0.2 mg/kg
IM
Once
Sedation
0.03–0.1 mg/kg
IV
Once
Sedation
0.1–0.3 mg/kg
IM
Once
Sedation
0.05–0.15 mg/kg
IV
Once
Epidural analgesia
0.05–0.07 mg/kg
EPIDURAL
Sheep
Use / stage
Dose
Route
Schedule
Instructions
Sedation
0.1–0.3 mg/kg
IM
Once
Sedation
0.05–0.1 mg/kg
IV
Once
Light standing sedation
0.01 mg/kg
IV
Once
Recumbent sedation
0.2 mg/kg
IM
Once
Use 20 mg/mL preparation; marked species sensitivity.
Goat
Use / stage
Dose
Route
Schedule
Instructions
Sedation
0.05–0.5 mg/kg
IM
Once
Sedation
0.01–0.5 mg/kg
IV
Once
Light standing sedation
0.01 mg/kg
IV
Once
Recumbent sedation
0.2 mg/kg
IM
Once
Use 20 mg/mL preparation; marked species sensitivity.
Ferrets
Use / stage
Dose
Route
Schedule
Instructions
Sedation or analgesia
0.5–2 mg/kg
IM, SC
Often a combination with antimuscarinic or opioid.
Birds
Use / stage
Dose
Route
Schedule
Instructions
Sedative adjunct
1–4 mg/kg
IM
For ketamine anesthesia; avoid debilitated birds due to cardiac depression.
Overdose can cause profound CNS/respiratory depression, bradyarrhythmias, hypotension or seizures. Support ventilation and perfusion and consider a suitable alpha2 antagonist.
Monitor rhythm, perfusion, ventilation, regurgitation and recovery. Lower equine doses favor standing restraint; draft horses can be more sensitive. Routine atropine premedication is not required solely for the expected low pulse.
Significant adverse effects can be reversed with an appropriate alpha2 antagonist.
Combined epidural protocols include dogs xylazine 0.02 mg/kg plus morphine 0.1 mg/kg to 0.26 mL/kg, and horses xylazine 0.17 mg/kg plus lidocaine 0.22 mg/kg in the first coccygeal space; recumbency/ataxia may occur. Do not assign these combined durations to xylazine alone.
Small-mammal anesthesia combinations: rabbits ketamine 35 + xylazine 5 mg/kg IM, or ketamine 25 + xylazine 5 with butorphanol 0.1 or acepromazine 1 mg/kg IM. IP combinations include gerbil ketamine 50/xylazine 2, guinea pig 40/5, hamster 200/10, mouse 80/10 and rat 75/10 mg/kg; an alternative rodent protocol uses xylazine 5/ketamine 50/atropine 0.05 mg/kg IP. These are joint protocols, not isolated sedative regimens.
Bovine standing BXK combination: butorphanol 0.01-0.025, xylazine 0.02-0.05 and ketamine 0.04-0.1 mg/kg IM. Initial suggested totals for animals above 450 kg are no more than butorphanol 10 mg and xylazine 20 mg. Camelid IM combination: alpaca butorphanol 0.046/xylazine 0.46/ketamine 4.6 mg/kg; llama 0.037/0.37/3.7 mg/kg. Up to half the original ketamine/xylazine amounts may extend anesthesia; no final compounded-vial mL concentration is inferred.
