Chemicals / Complex Chemical Agents/ Chemical:

Xylazine (with special reference to Ruminants, Hedgehogs, Elephants, Bears, Lagomorphs, Ferrets, Great Apes and Cranes)




Information in this page has been entered to support the current volumes of Wildpro and further information will be added as new volumes are completed. This page is not intended to substitute for the manufacturer's data sheet and the information is not yet complete for all species, or for all contra-indications etc.

CAUTION: Before any pharmaceutical product is used, the manufacturer's data sheet, containing information on uses, dosage and administration, contra-indications, warnings etc., should always be consulted. It is important to remember that licensing of pharmaceutical products for use in a particular species/condition, as well as mandatory meat and milk withdrawal times for food-producing animals, varies between countries and changes with time. Withdrawal times also may vary between different pharmaceutical formulations and depending on route of administration. In the EU, the prescription cascade must be followed (see LCofC1.2H and W564.Apr05.w1); note that specific restrictions apply for food-producing animals. In the USA, FARAD may be consulted regarding residues and meat and milk withdrawal times.

General Chemical Information

Alpha2-adrenergic agonist used mainly as a sedative and analgesic. (B201.6.w6, B263)

Return to Top of Page

Names and Formulae
Type Alpha2-adrenergic agonist structurally related to clonidine. (B263)
Alternative Names
Chemical Formula C12H16N2S. (W324)
Chemical Structure --
Molecular Weight 220.3318. (W324)
Related Chemicals Medetomidine, detomidine. (B201.6.w6)

Return to Top of Page

Physical Properties / Chemistry

White crystalline powder. (B266 - Data sheet for Rompun Dry Substance, Bayer plc.)

Melting point --
Boiling point --
Density --
Water solubility Xylazine hydrochloride: soluble. (B266 - Data sheet for Rompun Dry Substance, Bayer plc.)
Other solubility --
  • Weak organic base. (J234.2.w1)
  • Commercially prepared injection: pH 5.5. (B263)

Return to Top of Page

Pharmacology & General Information
  • Potent alpha2-adrenergic agonist (alpha2-adrenoceptor stimulant). (B201.6.w6, B263)
  • CNS effects:
    • Causes sedation and CNS depression. (B263)
    • Muscle relaxation is mediated through central nervous system pathways. (B263)
    • Emesis (in cats and sometimes in dogs, but not occurring in horses, cattle sheep, goats) is thought to be centrally mediated. (B263)
    • Depresses thermoregulatory mechanisms. (B263)
  • Cardiovascular effects: 
    • Initial increased total peripheral resistance and increased blood pressure. (B201.6.w6, B263)
    • Longer period of lowered (below baseline) blood pressure. (B201.6.w6, B263)
    • Bradycardia. (B263) Due to sino-atrial and atrioventricular heart block, partially in response to the initial hypertension. (B201.6.w6)
    • Second degree heart block or other arrhythmias may occur. (B263)
    • Overall decrease in cardiac output (up to 30%). (B263)
  • Respiratory effects:
    • At high doses may act as a respiratory depressant with decreases in tidal volume and respiratory rate, overall decrease in minute volume. (B263)
  • Insulin-related effects:
    • Decreases serum insulin levels which may lead to increased blood glucose levels (hyperglycaemia). (B201.6.w6, B263)
  • Renal effects:
Storage / Stability
  • Store below 30°C (86°F). (B263)
Legal Category (In UK) POM (B266)

Return to Top of Page


Associated Techniques




(Further Reading)
Click image for full contents list of ELECTRONIC LIBRARY

Authors Debra Bourne (V.w5)
Referees Suzanne I. Boardman (V.w6); Becki Lawson (V.w26)

Return to Top of Page

Therapeutic Information

  • Sedative/analgesic, with muscle-relaxant properties. (B263, B266)
  • Emetic in cats and sometimes in dogs. (B263)
Appropriate Use
  • As a sedative/analgesic. (B263)
  • As a sedative to facilitate handling. (B201.6.w6)
  • As a sedative, in conjunction with local anaesthesia, to allow minor procedures. (B201.6.w6)
  • For premedication before anaesthesia. (B201.6.w6)
    • Reduce anaesthetic induction agent by 50-75% to avoid fatal overdose. (B201.6.w6)
    • Concurrent atropine administration may be useful in dogs/cats to reduce salivation and reduce bradycardiac effects. (B201.6.w6)
  • In combination with ketamine for general anaesthesia. (B201.6.w6)
  • Epidural injection. (B201.6.w6)
  • As an emetic in cats. (B263); may be useful in cats/dogs which have not been starved for at least six hours prior to anaesthesia. (B201.6.w6)
  • As a sedative to facilitate handling of fractious animals, veterinary examination and for premedication for minor superficial operations, painful manipulative procedures and local or regional anaesthesia. (B266)
  • Analgesia for visceral pain; effects last about 45 minutes with dose stated below. (J15.22.w1)
    • Not suitable for analgesia in rams with urolithiasis as alpha-2 agonists increase urine production. (J15.22.w1)
  • In horses, apparently sedated individuals may still react to auditory stimuli (e.g. kicking, avoidance responses). (B263)
  • Considerable species-specific variability in sensitivity: ruminants require about a tenth of the equine dose while pigs require 20-30 times the ruminant dose. (B263)

Return to Top of Page

Pharmacokinetics and Drug Interactions
Absorption /Bioavailability

Bioavailability following intramuscular administration:

  • Incomplete, variable. (B263)
  • Horse: 
    • 40 to 48 %. (B263)
    • Approximately doubled dose required if intramuscular rather than intravenous administration is used. (B201.6.w6)
  • Sheep: 
    • 17 to 73 %. (B263)
    • Range 17 to 73 %, mean 40.8 %. (J234.2.w1)
    • Following intramuscular administration of 1.0 mg/kg in sheep weighing 42-65 kg, bioavailability was in the range 17 to 73% (mean +/- SD 40.75 +/- 23.81 %). (J289.4.w1)
  • Dog: 
    • 52 to 90 %. (B263)
Distribution Horse:
  • Onset of action following intravenous administration 1-2 minutes; maximum effect 3-10 minutes; duration of effect approximately 1.5 hours (dose-dependant). (B263); peak action following intravenous administration within 5 minutes and lasting for 15 minutes; sedative effect lasts 40-60 minutes. (B201.6.w6)
  • Onset of action following intravenous administration 3-5 minutes, following intramuscular or subcutaneous administration approximately 10-15 minutes; duration of analgesic effect 15-30 minutes; duration of sedative effect 1-2 hours (dose-dependent). (B201.6.w6, B263)
  • Onset of action following administration usually within 5 minutes; peak effect in 15 minutes. (B201.6.w6) Following intramuscular injection onset of action 5 to 10 minutes, maximum effect 15 minutes. (J234.2.w1)
  • For a dose of 0.2 mg/kg intravenously, t1/2α 1.21 min, V'd(area) 1.94 L/kg. (J234.2.w1)
  • Following intravenous administration of 0.2 mg/kg xylazine in cattle of weight 240-440 kg, the distribution half-life t1/2α was 1.205 minutes and the apparent volume of distribution Vd (area) was 1.944 L/kg. (J289.4.w1)
  • For a dose of 1.0 mg/kg intravenously, t1/2α 1.89 min, V'd(area) 2.74 L/kg. (J234.2.w1)
  • Following intramuscular injection onset of action 5 to 10 minutes, maximum effect 15 minutes, time to maximum concentration 14.7 minutes. (J234.2.w1)
  • Following intravenous administration of 1.0 mg/kg xylazine in sheep of weight 42 to 65 kg, the distribution half-life t1/2 was 1.889 minutes and the apparent volume of distribution Vd (area) was 2.740 L/kg. (J289.4.w1)
Plasma Protein binding / Storage --
Elimination Route
  • Extensive biotransformation. (J234.2.w1)
  • Extensive biotransformation in ruminants with peak excretion of metabolites at two to four hours after administration. (J234.2.w1)


  • Less than 1% unchanged xylazine is eliminated via urine in the first two hours after administration. (J234.2.w1)
Elimination half-life / Clearance Rate Plasma distribution half life 1.2-6 minutes following intravenous administration in dogs, horses, cattle and sheep. (J4.191.w1)

Serum half-life:

  • Horse: approximately 50 minutes. (B263)
  • Dog: approximately 30 minutes. (B263)

Full recovery:

  • Horse: two to three hours. (B263)
  • Dog/cat: two to four hours. (B263)


  • For a dose of 0.2 mg/kg intravenously, t1/2 β 36.5 min, Clβ 42 mL/kg/min. (J234.2.w1)
  • Following intravenous administration of 0.2 mg/kg xylazine in cattle of weight 240-440 kg, the half-life of elimination t1/2β was 36.48 min and clearance Clβ was 42 mL/kg/h. (J289.4.w1)
  • Note: it has been found not possible to detect xylazine during deep sedation of cattle which was induced by intramuscular administration of xylazine at 0.2 mg/kg. (J4.191.w1) Administration of xylazine at 0.2 mg/kg in cattle resulted in plasma concentrations below the limits of assay sensitivity (0.01 µg/mL). (J289.4.w1)
  • For a dose of 1.0 mg/kg intravenously, t1/2β 23.1 min, ClB 83 mL/kg/min. (J234.2.w1)
  • Following intravenous administration of 1.0 mg/kg xylazine in sheep of weight 42-65 kg the half-life of elimination t1/2β was 23.105 min and clearance ClB was 83 mL/kg/h. Following intramuscular injection of the same dose, t1/2β was 22.36 min. (J289.4.w1)
Drug Interactions
  • Physical compatibility (in the same syringe) reported with acepromazine, buprenorphine, butorphanol, chloral hydrate, ketamine, meperidine. (B263)
  • Increases risk of ventricular arrhythmias from epinephrine. (B263)
  • Potentially additive hypotension if used with acepromazine. (B263)
  • Additive CNS depression is possible if used together with other CNS depressants such as barbiturates, narcotics, anaesthetics, phenothiazines; reduced dosage of such agents may be required. (B263)
  • Should not be used in conjunction with other tranquillisers. (B263)
  • May be reversed using the alpha2-antagonist atipamezole. (B201.6.w6)

Return to Top of Page

Formulations available
  • Chanazine 2%, xylazine (as hydrochloride) 20 mg/mL, 25mL. (Chanelle) UK
  • Chanazine 10%, xylazine (as hydrochloride) 100 mg/mL, 50mL. (Chanelle) UK
  • Rompun 2%, xylazine (as hydrochloride) 20 mg/mL, 25mL. (Bayer, plc.) UK. (B201.6.w6)
  • Rompun Dry Substance, powder for reconstitution, xylazine (as hydrochloride) 500 mg. (Bayer, plc.). (B201.6.w6)
  • Virbaxyl 2%, xylazine (as hydrochloride) 20 mg/mL, 25mL. (Virbac) UK
  • Virbaxyl 10%, xylazine (as hydrochloride) 100 mg/mL, 50mL. (Virbac) UK
  • Xylazine 2%, xylazine (as hydrochloride) 20 mg/mL, 25mL. (Millpledge) UK
Doses / Administration Routes / Frequencies Cattle: More potent than in other domestic animal species. (J234.12.w1)
  • Pre-treatment with atropine may be used to decrease the bradycardia and hypersalivation. B263
  • 0.05-0.15 mg/kg intravenously or 0.1-0.33 mg/kg intramuscularly. (B263 - Thurman & Benson 1986)
    • Intramuscular injection, if used, should be given via an 18 or 20 gauge needle at least 1.5 inches long. (B263)
    • Intravenous route may stress cardiovascular function. (B263)
  • 0.044-0.11 mg/kg intravenously or 0.22 mg/kg intramuscularly. (B263)
  • 0.1-0.2 mg/kg intramuscularly for analgesia. Note: sedative with dose-dependant response; Brahman cattle are particularly sensitive. (J4.191.w12)
  • 0.05 to 0.30 mg/kg (0.25-1.5 mL of 2% solution per 100 kg) bodyweight, depending on the required degree of sedation, by intramuscular injection: fractious animals may need the higher end of this dose range. (B266) Initial effects within five minutes of intramuscular injection and maximal effect ten minutes later. The following effects are suggested:
    • 0.05 mg/kg "Sedation, with a slight decrease of muscle tone. The ability to stand is maintained." (B266 - Data for Rompun 2% Solution, Bayer, plc.)
    • 0.10 mg/kg "Sedation, marked decrease in muscle tone and some analgesia. The animal usually remains standing, but may lie down."(B266)
    • 0.20 mg/kg "Deep sedation, further decrease of muscle tone and a degree of analgesia. The animal lies down." (B266)
    • 0.30 mg/kg "Very deep sedation, a profound decrease in muscle tone and a degree of analgesia. The animal lies down." (B266)

Sheep & goats:

  • To be used with extreme caution. (B263)
  • 0.05-0.1 mg/kg intravenously or 0.10-0.22 mg/kg intramuscularly. (B263, B362.w2 )
  • 0.044 - 0.11 mg/kg intravenously or 0.22 mg/kg intramuscularly. (B263)
  • 0.05-0.2 mg/kg; good analgesic. (B217.69.w69)
  • 0.05-0.1 mg/kg intravenously or intramuscularly provides good analgesia against visceral pain for about 45 minutes. (J15.22.w1)
  • 0.05-0.02 mg/kg intramuscularly. Note: "usually in conjunction with adjunctive sedative or anesthetic." (J4.191.w12)

Experimental data in sheep:

  • Alpha-2 adrenoceptor agonists are effective against visceral pain but their effects last only a short time (e.g. 0.05 to 0.1 mg/kg xylazine intramuscularly or intravenously provides pain relief for 45 minutes. (J15.22.w1)
    • "The α-2 adrenoceptor agonists would seem to hold the key to successful acute pain management in the sheep." (J24.73.w1)
    • Xylazine at 50 µg/kg intravenously had clear anti-nociceptive activity for both thermal and mechanical pressure threshold detection. Within five minutes of administration the thermal threshold from about 55°C to higher than 70 °C (maximum cut-out) and remained above 70°C for thirty minutes, then gradually returned to normal after about 60 minutes. Similarly xylazine injection resulted in an immediate increase in mechanical threshold to above the pre-set maximum value and returned to pre-xylazine values after about 45 minutes. The anti-nociceptive effect in either case was eliminated by pretreatment with the alpha-2 antagonist idazoxan, indicating that the analgesia demonstrated was mediated by alpha-2 adrenoceptors. (J289.10.w2)
    • Xylazine at 50 µg/kg (0.05 mg/kg) intramuscularly produced an anti-nociceptive effect in adult sheep, as measured by the electrical current required to produce leg withdrawal, for the period 15 to 60 minutes post injection (for a statistically significant effect, P<0.05). With 0.1 mg/kg the effect occurred faster and lasted from 3-60 minutes post injection with a slightly greater increase in threshold (180% above baseline rather than 170% for the lower dose), while a dose of 0.2 mg/kg produced a statistically significant increase above baseline for the period 2 to 60 minutes and the peak effect was 510.3% above baseline at 14 minutes, however three of six sheep showed significant sedation at this dose level (head drooping and reduced alertness were observed). (J24.73.w1)
    • Xylazine at 50 µg/kg intramuscularly had a clear anti-nociceptive effect in lambs, as indicated by a test with an electrical current, without producing any visible signs of sedation such as ptosis or reduced alertness and without affecting responses to other stimuli such as noise or touch. (J21.70.w1)
    • Xylazine at 0.02 mg/kg intramuscularly plus ketamine at 1 mg/kg intramuscularly in anaesthetised sheep subjected to abdominal surgery caused some increase (P = 0.002) in the time taken for ewes to lift their heads following anaesthesia, indicating some sedation, but no difference in the time to standing. The number of unsuccessful attempts to stand was decreased in the treated ewes, indicating a smoother recovery and possibly reduced pain in these individuals. Plasma cortisol levels were slightly lower (P = 0.018) over the first five days post operation than in ewes not given the drugs, although the levels were within the normal range in both treated and untreated ewes. (J24.79.w2)
    • Xylazine at 50 µg/kg intravenously provided analgesia, indicated by an increase in the threshold to a noxious mechanical stimulus. However in sheep with footrot which had been present for at least one week (i.e. individuals in chronic pain) analgesia declined more rapidly than in control non-lame sheep, the difference being significant by 25 minutes; this difference was also detected in sheep after treatment, in which resolution of the clinical condition had occurred. (J289.14.w)

Erinaceus europaeus - West European Hedgehog:

  • 1.0 - 2.5 mg/kg intramuscularly. For sedation. (D107)
  • Xylazine 1 - 2.5 mg/kg / ketamine 5 - 15 mg/kg. For anaesthesia; reverse the xylazine with atipamezole 1.0 mg/kg. (D107)

Atelerix albiventris - Four-toed hedgehog:

  • 0.5 - 1.0 mg/kg intramuscularly. For anaesthesia; may be administered with ketamine. (B267)
  • 0.5 - 1.0 mg/kg. (J204.59.w1)

"Hedgehog" (species not distinguished between Atelerix albiventris - Four-toed hedgehog or Erinaceus europaeus - West European Hedgehog):

  • Ketamine 5 - 20 mg/kg intramuscularly in combination with 0.5 - 1.0 mg/kg xylazine intramuscularly; N.B. duration of sedation and recovery may be prolonged with injectable anaesthetics. (J34.24.w1)


The following information is taken with permission directly from the Elephant Care International website (W580.Aug2005.w32):


CAUTION! Sedative and anesthetic drug dosages for African elephants often vary from those for Asian elephants. Do not assume that the recommendations for one species can be applied to the other. Significant variation may also occur between individual elephants. Higher doses may be needed in wild or excited animals. Unless otherwise specified, doses refer to captive elephants. The information provided here should be used as a guideline only. Consultation with experienced colleagues is advised. 

a,l) Xylazine 100-200 mg/metric ton for Asian elephants. Extreme aggressiveness, musth, painful conditions, and ambient disturbances may necessitate higher doses (Cheeran, 2002,1992). 

b) 0.10-0.11 mg/kg xylazine IM for Asian elephants; can be combined with acepromazine or ketamine; the dose of individual drugs can be reduced up to 50% when combinations are used (Nayer 2002). 

c) Xylazine at a dose of 100-300 mg in adult Asian elephants (approximately 4-10 mg/ 100 kg body weight) injected slowly intravenously resulted in good sedative, analgesic, and muscle relaxing effects in 21 Asian elephants undergoing blood collection, biopsies and ultrasound examinations. The author advises that yohimbine or atipamezole be readily available in case of overdose or inadvertent human exposure (1mg/kg can be lethal in man) (Rietschel 2001).

 d) In Asian elephants: xylazine alone (0.1 mg/kg) or in combination with ketamine (1.25: 1 ratio) (Sarma et al. 2001). 

e) Xylazine at dosages of 0.18-0.33 mg/kg (total doses 600-1000 mg) was used to sedate 3 African elephants to load into a trailer a distance of about 50 m away. The procedure was accomplished but the sedation was rated as fair (Ramsey, 2000). 

f) * Adverse effect: A 27 year-old male Asian elephant with mild bilateral corneal opacities was laid in lateral recumbency, injected with 150 mg xylazine slowly via the caudal auricular vein and then allowed to stand. After 2.5 minutes he tilted his head upwards and backwards in a tentative gait. At 4-5 minutes he trumpetted loudly and started to shake his head vigorously, followed by complete delirium. After 10 minutes of violent excitement, he gradually became normal but his degree of sedation was minimal. An additional 50 mg of xylazine was given IV and the elephant became profoundly sedated. He was reversed with 60 mg yohimbine IV. The author suggests that the elephant’s visual impairment may have caused the reaction (Sarma, 1999). 
g) Intravenous xylazine (33-72 µg/kg) was titrated to achieve standing sedation with responsiveness to voice commands in a 5000 kg male Asian elephant sedated on 3 occasions for treatment of a foot abscess. Partial reversal with atipamezole made the animal more responsive in cases of heavy sedation (Honeyman 1998). 

h) Xylazine doses ranging from 100-550 mg with a mean of 0.209 mg/kg body weight were used to capture 8 wild Asian elephants (Bosi 1997). 

i) Captive Asian elephants: For sedation: 0.04-0.08 mg/kg (180-360 mg total dose);For immobilization 0.15-0.20 mg/kg alone or 0.12 mg/kg xylazine in combination with 0.33 mg/kg ketamine.
 Captive African elephants: For sedation: 0.08-0.10 mg/kg (100-640 mg total dose);For immobilization (opiates are preferred): 0.15-0.20 mg/kg xylazine;
For babies and juveniles: 0.14 mg/kg xylazine in combination with 1.14 mg/kg ketamine (Fowler, 1995).
j) Adult 700 mg; juvenile-adult 200-600mg; baby-juvenile 20-160 (species not specified); adult Asian elephant for translocation 150-2850 mg (Kock 1993). (Author’s (Mikota) note: Theanimal category and drug dose column headings for xylazine are misaligned in this reference and may cause confusion. The doses listed here have been correctly matched to their respective age categories. Regarding the Asian elephant dose, also note that in the original source (Lahiri-Choudhury, 1992), 2850 mg represents a combination of xylazine and ketamine. It does not represent a high end dose of xylazine alone. In this comparative study, 2850 mg was the maximum given to an individual elephant (over the time period that included capture and translocation, not as a single dose) and the maximum dose used during 24 hours. 
k) 100 mg/ton is an ideal dose for Asian elephants (Appayya, 1992). 
l) see (a) 

m) In a comparison of Asian elephant capture and translocation techniques, 400 mg xylazine was the maximum single dose used in Malaysia (tusker over 9’6”) and 150 mg was the maximum dose used in West Bengal (tusker 8’2”). Maximum total on a single elephant were 2100 mg over 4 days (Malaysia) and 1525 mg (West Bengal). Maximum during 24 hours was 1500 mg (Malaysia) and 925 mg (West Bengal). (Lahiri- Choudhury, 1992). 
n) Xylazine, administered IM was used to induce surgical anesthesia in 8 Asian elephants. A dose of 150 mg in a1500 kg baby tusker and a dose of 400 mg in a 3000 kg tusker resulted in standing immobilization. Recumbent immobilization was achieved with doses of 400 mg (3500 kg tuskers) and 450 mg (4000 kg tusker), and with combinations of 350 mg xylazine + 350 mg ketamine (3000 kg cow), 300 mg xylazine + 150 mg acepromazine (2500 kg cow) and 350 mg xylazine + 150 mg acepromazine (3000 kg cow). Induction occurred in 10-15 minutes and duration of anesthesia varied from 30-60 minutes and provided sufficient analgesia for a variety of surgical procedures (Nayar, 1992).

Elephant References:
a) Cheeran,J.V., Chandrasekharan,K., and Radhakrishnan,K. 2002. Tranquilization and translocation of elephants. Journal of Indian Veterinary Association Kerala 7:(3):42-46

b) Nayar,K.N.M., Chandrasekharan,K., and Radhakrishnan,K. 2002. Management of surgical affections in captive elephants. Journal of Indian Veterinary Association Kerala 7:(3):55-59

c) Rietschel,W., Hildebrandt,T., Goritz,F., and Ratanakorn,P. 2001. Sedation of Thai Working Elephants with Xylazine and Atipamezole as a Reversal. A Research Update on Elephants and Rhinos; Proceedings of the International Elephant and Rhino Research Symposium, Vienna, June 7-11, 2001. Pages: 121-123

d) Sarma,K.K. and Pathak,S.C. 2001. Cardio vascular response to xylazine and Hellabrunn mixture with Yohimbine as reversal agent in Asian elephants. Indian Veterinary Journal 78:(5):400-492 Abstract: Xylazine (0.1 mg/kg body weight) produced highly significant bradycardia and hypotension in recumbent Asian elephants, with a peak depression observed at the 30th minute for heart rate and 30th minute in the mean arterial pressure (MAP). Ketamine (1.25 : 1 ratio with xylazine) mildly marginalised the bradycardia, but remarkably improved the MAP. Yohimbine, used to reverse the sedation produced by xylazine did not appear to influence these parameters to any appreciable levels.

e) Ramsay,E. 2000. Standing sedation and tranquilization in captive African elephants (Loxodonta africana). Proc. Am. Assoc. Zoo Vet. Pages: 111-114

f) Sarma,K.K. 1999. Bizarre behaviour of an elephant during xylazine anaesthesia. Indian Veterinary Journal 76:(11):1018-1019

g) Honeyman,V.L., Cooper,R.M., and Black,S.R. 1998. A protected contact approach to anesthesia and medical management of an Asian elephant (Elephas maximus).  Proceedings AAZV and AAWV Joint Conference. Pages: 338-341

h) Bosi,E.J., Kilbourn,A.M., Andau,M., and Tambing,E. 1997. Translocation of wild Asian elephants (Elephas maximus) in Sabah, Malaysia. Proceedings American Association of Zoo Veterinarians. Pages: 302 Abstract: The East Malaysian State of Sabah is believed to be home to about 1000 wild Asian elephants (Elephas maximus). Some forest habitat has been lost through agricultural development. In some cases, elephants are stranded in small pockets of forest which are unable to sustain them. The Wildlife Department of Sabah has adopted a policy of capturing and translocating these animals to wildlife forest reserves. The capture of these wild animals is made possible using chemicals such as Immobilon® (etorphine HCl and acepromazine maleate) and Xylazine-100 (xylazine HCl). The reversal agents are Revivon (Diprenorphine) and Reverzine (Yohimbine), respectively. A recent capture and translocation exercise carried out involving eight wild elephants employed xylazine hydrochloride. The dose of xylazine used was calculated based on the diameter of the front footprint which provides information on body dimensions when actual weights are not available. Xylazine doses used ranged from 100-550 mg with a mean of 0.209 mg/kg body weight. Sedation was observed within 26 min after the darting. The animals were then shackled and tethered. The time for the capture operations ranged from 27-110 mins, with a mean of 72 min. Xylazine is used again during the loading of the animals onto the lorries. It is an effective sedative for wild elephants which can be adjusted or reversed. The choice and used of this drug depends entirely on the ability to track the animal after darting and the ability to maneuver the captive elephants into suitable locations for tethering prior to loading. Heavy machinery is required to load the animals, unlike most other wild Asian elephant translocations where trained elephants are used to facilitate loading.

i) Fowler,M.E., 1995. Elephants. In: Restraint and handling of wild and domestic animals. Iowa State University Press, Ames, Iowa, USA pp. 265-269

j) Kock,R.A., Morkel,P., and Kock,M.D., 1993. Current immobilization procedures used in elephants. In: Fowler,M.E. (Editor), Zoo and Wild Animal Medicine Current Therapy 3. W.B. Saunders Company, Philadelphia, PA, USA pp. 436-441

k) Appayya,M.K. and Khadri,S.S.M.S., 1992. Chemical capture of wild elephants and their translocation carried out in Karnataka state. In: Silas,E.G., Nair,M.K., and Nirmalan,G. (Editors), The Asian Elephant: Ecology, Biology, Diseases, Conservation and Management (Proceedings of the National Symposium on the Asian Elephant held at the Kerala Agricultural University, Trichur, India, January 1989). Kerala Agricultural University, Trichur, India pp. 107-112

l) Cheeran,J.V., Chandrasekharan,K., and Radhakrishnan,K., 1992. Tranquilization and translocation of elephants. In: Silas,E.G., Nair,M.K., and Nirmalan,G. (Editors), The Asian Elephant: Ecology, Biology, Diseases, Conservation and Management (Proceedings of the National Symposium on the Asian Elephant held at the Kerala Agricultural University, Trichur, India, January 1989). Kerala Agricultural University, Trichur, India pp. 176  Abstract: (Full text): A total of 140 captive rogue tuskers were successfully tranquilized and translocated during the period for April 1979 to December 1988. Most of the animals were those used in festivals or in lumbering operations. The requests handled by the tranquilization team were of urgent nature and no kunkies were available to assist the operation. Hence the animals were tranquilized retaining certain amount of ambulatory property and not allowing the animals to assume recumbency. After ascertaining complete sedation which took nearly 45 minutes after darting the limbs were noosed with polypropylene ropes and pulled by volunteers numbering from 15 to 20 on each rope on the forelimb. The animals were also given oral and percussion commands and coaxed to move. Animals could be moved on an average of 100 meters to be tied in a safe tethering area. The chemical used at first was nicotine and was subsequently replaced by xylazine alone or its combinations for better margin of safety. The combination of xylazine with acepromazine and ketamine was discarded due to photosensitization of elephants and subsequent skin lesions on the back of the elephants. The dose of xylazine varied from 100 to 120 mg/ton body weight. The data show that 85% of the cases were attended while the bulls were in premusth or post-musth period indicating lack of sufficient precaution taken by the mahouts.

m) Lahiri-Choudhury,D.K., 1992. Translocation of wild elephants. In: Silas,E.G., Nair,M.K., and Nirmalan,G. (Editors), The Asian Elephant: Ecology, Biology, Diseases, Conservation and Management (Proceedings of the National Symposium on the Asian Elephant held at the Kerala Agricultural University, Trichur, India, January 1989). Kerala Agricultural University, Trichur, India pp. 91-106

n) Nayar,K.N.M., Radhakrishnan,K., Chandrasekharan,K., Cheeran,J.V., Ravindran,S., and George,P.O., 1992. Anaesthesia for surgical manipulations in the elephant. In: Silas,E.G., Nair,M.K., and Nirmalan,G. (Editors), The Asian Elephant: Ecology, Biology, Diseases, Conservation and Management (Proceedings of the National Symposium on the Asian Elephant held at the Kerala Agricultural University, Trichur, India, January 1989). Kerala Agricultural University, Trichur, India pp. 156-158 Abstract: Anaesthesia using chloral hydrate, thiopentone sodium, xylazine and ketamine was induced in ten elephants. The effects, duration of induction and anaesthesia were recorded. Post anaesthesia complications were not encountered in any of the animals. Surgical manipulations could be carried out under anaesthesia induced with these drugs.

o) Pathak,S.C. 1991. Xylazine-ketamine anesthesia in Indian elephant (Elephas maximus indicus). - trial on 53 clinical cases. International Seminar on Veterinary Medicine in Wild and Captive Animals, Nov. 8-10, Bangalore, India. Pages: 21 Abstract: Veterinarians are often required to attend and undertake surgery on elephants. Unless the animal is deeply sedated or anesthetized certain works become impractical. Xylazine has proved to be a good sedative and analgesic in elephants. This drug is not freely available in India and is costly. The drug is usually used by intramuscular route but to reduce the dose it has been used intravenously. Intravenous use may be risky for its bradycardia effect and fall in cardiac output. Ketamine, on the other hand, has no depressant effect on the cardiovascular and respiratory system but produces muscular tremor and stiffness of the skeletal muscle. Combination of Xylazine and Ketamine minimizes the undesirable aspects of both the drugs. A mixture containing 100-150 mg xylazine and 50-100 mg ketamine injected intravascularly to the laterally recumbent elephant produced quick, safe and dependable analgesia, anesthesia, and muscular relaxation. Surgical operations like tusk extraction, bullet extraction, umbilical and pleural herniorraphy, trunk injury, extensive wound repair, etc. were performed in 53 elephants. Recovery followed without excitement and untoward effect based on the observations of this trial on clinical cases, combination of Xylazine and Ketamine is recommended in elephant.

p) Pathak,S.C., Saikia,J., Lahon,D.K., Deka,K.N., Barua,S.K., Dewan,J.N., and Vety,A.H. 1990. Attempted ventral herniorrhaphy in an Asian elephant (Elephas maximus) using xylazine sedation. Journal of Zoo and Wildlife Medicine 21:(2):234-235 Abstract: Ventral herniorrhaphy in a female Asian elephant (Elephas maximus) under xylazine hydrochloride sedation was attempted. A dose of 0.16 mg/kg body weight was adequate to produce sedation, analgesia, and muscle relaxation for the procedure. The postoperative management of the surgical wound was difficult and resulted in the failure of the surgery.

q) Welsch,B., Jacobson,E.R., Kollias,G.V., Kramer,L., Gardner,H., and Page,C.D. 1989. Tusk extraction in the African elephant (Loxodonta africana). Journal of Zoo and Wildlife Medicine 20:(4):446-453 Abstract: Unilateral dentoalveolar abscesses and/or tusk fractures were identified and tusk extractions performed in seven 3.5-21-yr-old African elephants (Loxodonta africana) of both sexes weighing 650-3,000 kg. Following immobilization with etorphine hydrochloride or carfentanil citrate, six of seven elephants were intubated and maintained on a 1-1.5% halothane in oxygen mixture; one elephant was maintained in lateral recumbency by multiple i.v. injections of etorphine. All elephants were positioned with the affected tusk up. For one elephant, two surgical procedures were required to remove the tusk. In six of seven elephants, the tusks were sectioned transversely and the tusk wall thinned by enlarging the pulp cavity with carbide burs. In those tusks with remaining pulp, the pulp was removed with stainless steel rods and hooks. Next, the tusk was sectioned longitudinally into three or four segments using a wood saw within the pulp chamber. bone gouges, osteotomes, and a mallet were used to free the outer epithelial and alveolar attachments from the tusk. Starting with the smallest segment, the sections were removed using long screwdriver-shaped stainless steel rods. The alveolar chamber was then periodically flushed postsurgically with a dilute organic iodine solution. For six of seven elephants, complete granulation of the alveolar chamber was evident by 4 mo postsurgery; the seventh elephant showed partial healing with granulation tissue at 2 mo following surgery.

r) Heard,D.J., Kollias,G.V., Webb,A.I., Jacobson,E.R., and Brock,K.A. 1988. Use of halothane to maintain anesthesia induced with etorphine in juvenile African elephants. Journal of the American Veterinary Medical Association 193:254-256 Excerpts: Sixteen 3- to 5-year-old African elephants were anesthetized one or more times for a total of 27 diagnostic and surgical procedures. Xylazine (0.1 ± 0.04 mg/kg of body weight, mean ± SD) and ketamine (0.6 ± 0.13 mg/kg) administered IM induced good chemical restraint in standing juvenile elephants during a 45-minute transport period before administration of general anesthesia. After IM or IV administration of etorphine (1.9 ± 0.56 micrograms/kg), the mean time to lateral recumbency was 20 ± 6.6 and 3 ± 0.0 minutes, respectively. The mean heart rate, systolic blood pressure, and respiration rate during all procedures was 50 ± 12 beats/min, 106 ± 19 mm of Hg, and 10 ± 3 breaths/min, respectively. Cardiac arrhythmias were detected during 2 procedures. In one elephant paroxysmal ventricular tachycardia was detected and the procedure terminated when the arrhythmia failed to stabilize after multiple doses of lidocaine (1 mg/kg, IV). In another elephant, second degree atrioventricular block returned to normal sinus rhythm after IV administration of atropine (0.04 mg/kg).
In one elephant, low mean blood pressure (54 mm of Hg) responded to reduction in halothane (vaporizer setting 1 to 0.75%) and slow infusion of dobutamine HCl ((250 mg/1,000 ml) given to effect. The systolic blood pressure increased to 90 mm of Hg and remained high with a continuous infusion of dobutamine (5 µg/kg/min).
Immediately after induction in another elephant, profound respiratory depression (< 1 breath / minute) and palpably weak arterial pulse were identified. Intravenous administration of diprenorphine at half the recommended reversal dose resulted in improvement of respiration and palpable arterial pulse, without the elephant developing signs of complete anesthetic reversal. Alterations in systolic blood pressure, ear flapping, and trunk muscle tone were useful for monitoring depth of anesthesia. Results indicated that halothane in oxygen was effective for maintenance of surgical anesthesia in juvenile African elephants after induction with etorphine. Note: A correction appeared in a later volume 193(6): p.721.

s) Allen,J.L. 1986. Use of tolazoline as an antagonist to xylazine-ketamine-induced immobilization in African elephants. American Journal of Veterinary Research 47:(4):781-783 Abstract: A group of 15 African elephants (Loxodonta africana) were immobilized with a combination of xylazine (0.2 mg/kg of body weight, IM) and ketamine (1 to 1.5 mg/kg of body weight, IM). Ten of the African elephants were allowed to remain recumbent for 30 minutes and the remaining 5 elephants, for 45 minutes before they were given tolazoline (0.5 mg/kg of body weight, IV). For the group of 15, the mean induction time (the time required from injection of the xylazine-ketamine combination until onset of recumbency) was 14.2 ± 4.35 minutes (mean ± SD), and standing time (the time required from the tolazoline injection until the elephant stood without stimulation or assistance) was 2.8 ± 0.68 minutes. All of the elephants were physically stimulated (by pushing, slapping, shouting) before they were given tolazoline, and none could be aroused. After tolazoline was given and the elephant was aroused, relapses to recumbency did not occur. Recovery was characterized by mild somnolence in an otherwise alert and responsive animal. Failure (no arousal) rates were 0% (95% confidence interval, 0 to 0.3085) for elephants given tolazoline after 30 minutes of recumbency and 100% for elephants that were not given tolazoline. There was no significant (P less than 0.05) difference in standing time 30 or 45 minutes after tolazoline injection.

t) Schmidt,M.J., 1986. Proboscidea (Elephants). In: Fowler,M.E. (Editor), Zoo and wild animal medicine. W.B. Saunders, Philadelphia,PA, USA pp. 884-923

u) Jacobson,E.R., Allen,J., Martin,H., and Kollias,G.V. 1985. Effects of yohimbine on combined xylazine-ketamine-induced sedation and immobilization in juvenile African elephants. Journal of the American Veterinary Medical Association 187:(11):1195-1198 Abstract: Twenty-two juvenile African elephants were given a combination of xylazine (mean +/- SD = 0.14 +/- 0.03 mg/kg of body weight) and ketamine (1.14 +/- 0.21 mg/kg) as a single IM injection; one elephant was immobilized twice, 77 days apart. After injection, 14 elephants were immobilized, 4 were sedated deeply, 2 were sedated moderately, and 2 were sedated minimally. Immobilized elephants had a mean immobilization time of 11.6 +/- 6.9 minutes. At the conclusion of a variety of clinical procedures, 12 of the 14 elephants immobilized with a single dose combination of xylazine and ketamine were given yohimbine (0.13 +/- 0.03 mg/kg) IV, and the remaining 2 elephants were allowed to recover spontaneously; the elephants given yohimbine had a mean standing time of 2.4 +/- 1.1 minutes. Of the 8 sedated elephants, 5 were given an additional dose of combined xylazine (0.08 +/- 0.03 mg/kg), and ketamine (0.61 +/- 0.19 mg/kg) IM, and 1 elephant was given ketamine (0.47 mg/kg) IV. After injection, 4 of the 8 elephants were recumbent laterally within 17 minutes and 2 remained standing, under deep sedation. Seven of the 8 elephants were given yohimbine (0.13 +/- 0.03 mg/kg) IV; all were ambulatory in 2 minutes. Results indicated that yohimbine may be useful in controlling duration of xylazine-ketamine sedation and immobilization in juvenile African elephants.

v) Schmidt,M.J. 1983. Antagonism of xylazine sedation by yohimbine and 4-aminopyridine in an adult Asian elephant (Elephas maximus). Journal of Zoo Animal Medicine 14:94-97 Abstract: Heavy xylazine sedation was successfully antagonized by intravenous injection of yohimbine and 4-aminopyridine (4-AP) in an adult female Asian elephant (Elephas maximus) prior to euthanasia. A total xylazine dose of 1,200 mg intramuscularly plus 600 mg intravenously (approximately 0.33 mg/kg body weight) was given resulting in heavy sedation. After 50 minutes of deep recumbent sedation, 425 mg yohimbine and 1,000 mg of 4-AP were administered intravenously. Xylazine sedation was antagonized and the elephant was up and walking around within 5 minutes of antagonist administration. The elephant remained standing for other 3 hours; at which point euthanasia was performed.

w) Bongso,T.A. 1980. Sedation of the Asian elephant with xylazine. Journal of the American Veterinary Medical Association 177:(9):783 Abstract: (Full text): Doses of 100 to 300 mg of a 10% solution of xylazine satisfactorily sedated 6 elephants ranging from 150 to 255 cm shoulder height. At these dosages, all animals were sedated in the standing position. The time taken to produce the initial signs of sedation ranged from 10+4 to 20+4 minutes, and the effects lasted from 60+8 to 100+15 minutes. The time taken from injection to complete recovery ranged from 360+31 to 540+21 minutes. Recovery was uncomplicated. Repeated administration of as much as 7 injections per animal at intervals of 3 to 4 days had no adverse effects. Disturbances during induction delayed the onset of action of the drug –also see T.A. Bongso in Vet Rec, 105, (November 10, 1979): 442.

See also:

Sharma S.P. 1997. Surgical treatment of gunshot wounds under xylazine and ketamine anaesthesia in an elephant: clinical case report. Indian Veterinary Journal 74:(11):973-974

Aik,S.S. 1992. Preliminary observations on the training of Burmese elephants using xylazine. New Zealand Veterinary Journal 40:(2):81-84 Abstract: A traditional elephant training method was chosen to be modified by the use of xylazine as a sedative and muscle relaxant. Three elephant calves with different degrees of tameness were trained using xylazine. The drug was helpful in the training process. Xylazine made restraint of the elephants much easier and safer. During training, repeated doses of xylazine were used to prevent beatings, the wounds worsening and to pacify the elephants. The tamest elephant calf was punished less and took less time to be trained than the others. It is concluded that it is important to play with elephant calves to win their acceptance of man.
Cheeran,J.V., Chandrasekharan,K., and Radhakrishnan,K., 1992. Transportation of elephants by rail. In: Silas,E.G., Nair,M.K., and Nirmalan,G. (Editors), The Asian Elephant: Ecology, Biology, Diseases, Conservation and Management (Proceedings of the National Symposium on the Asian Elephant held at the Kerala Agricultural University, Trichur, India, January 1989). Kerala Agricultural University, Trichur, India pp. 120-12
Lance,W.R. 1991. New pharmaceutical tools for the 1990's. Proceedings of the American Association of Zoo Veterinarians 354-359

Morton,D.J. and Kock,M.D. 1991. Stability of hyaluronidase in solution with etorphine and xylazine. J.Zoo and Wildlife Medicine 22:(3):345-347 Abstract: During capture of free-living wildlife, stress is potentially the greatest problem encountered. For this reason, reduction in induction time during immobilization is of paramount importance. Hyaluronidase reduces induction times, although no reports have assessed stability of the enzyme in drug mixtures used for chemical capture. This report presents information on the stability of hyaluronidase in combination with etorphine and xylazine, one of the most common drug mixtures used in chemical immobilization of wildlife. Hyaluronidase activity remains high for at least 48 hr, provided storage temperatures can be maintained at less than or equal to 30ş C. Storage at greater than or equal to 40şC is associated with rapid loss of enzyme activity in the mixture.

Jacobson,E.R. 1988. Chemical restraint and anesthesia of elephants. Proc.Ann.Elephant Workshop 9. Pages: 112-119

Heard,D.J., Jacobson,E.R., and Brock,K.A. 1986. Effects of oxygen supplementation on blood gas values in chemically restrained juvenile African elephants. Journal of the American Veterinary Medical Association 189:(9):1071-1074 Abstract: Arterial oxygen and carbon dioxide tensions were determined in sedated immature African elephants and in elephants immobilized with etorphine hydrochloride or with an etorphine-ketamine combination. For manipulative and surgical procedures, the Hudson demand value was used for oxygen supplementation during 6 procedures, and insufflation was used during 2 procedures. The Hudson demand value was more effective than insufflation in sustaining adequate arterial oxygenation.

Kock,N., Kock,M., Arif,A., and Wahid,M.N.S.A. 1984. Immobilization techniques and complications associated with a bull Indian elephant (Elephas maximus indicus) during musth. Proc.Am.Assoc.Zoo Vet. Pages: 68-74 Summary: An Asian bull in musth (estimated weight 4500 kg) was immobilized six times. Three drugs were used either alone or in combination. A mixture of etorphine and acetylpromazine (Immobilon®) was used effectively on three occasions at an average dose of 0.48 ml/1000kg. Xylazine (0.1 mg/kg) used alone was ineffective on two occasions and was supplemented with Immobilon. When Immobilon was used after the xylazine, the dose was reduced to 0.2 ml / 1000 kg. (Kock 1984). (Author’s (Mikota) note: xylazine dose given as mg/kg and etorphine dose given as ml in original article).

Jacob,V., Cheeran,K., Chandrasekharan,K., and Radhakrishnan,K. 1983. Immobilization of elephant in musth using xylazine hydrochloride. 7th Annual Symposium of the Indian Society of Veterinary Surgeons. Pages: 62
Fowler,M.E. 1981. Problems with immobilizing and anesthetizing elephants. Proceedings of the American Association of Zoo Veterinarians 87-91

Bongso,T.A. 1980. Use of xylazine for the transport of elephants by air. Vet Rec 107:(21):492

Schmidt,M.J. 1975. The use of xylazine in captive Asian elephants. Proc.Am.Assoc.Zoo Vet. Pages: 1-11

Schmidt,M.J. 1975. A preliminary report on the use of rompun in captive Asian elephants. Journal of Zoo Animal Medicine 6:13-21


1) In combination with Ketamine (see: Xylazine-Ketamine Anaesthesia in Bears):

  • Usually a 1:2 xylazine:ketamine ratio or a 1:1 ratio. (B10.48.w43) 
  • Xylazine 3 - 9 mg/kg + Ketamine 3-9 mg/kg OR xylazine 2 - 4.5 mg/kg + ketamine 5 - 9 mg/kg. (B10.48.w43)
  • Xylazine 2 mg/kg plus Ketamine 4-10 mg/kg. (B16.9.w9)
  • Xylazine 1 - 2 mg/kg plus Ketamine 5 mg/kg immobilises most bear species. (J213.4.w3)
  • Xylazine 2 mg/kg plus ketamine 5 - 8 mg/kg. (B407.w18)
  • Ursus americanus - American black bear: 
    • Xylazine 2 mg/kg + ketamine 4 mg/kg. (D156.w2)
    • Approximately 2:1 ketamine:xylazine ratio (1.5-17.1 mg ketamine + 0.9-10.0 mg/kg xylazine). (J1.15.w11)
    • Range 4 mg/kg ketamine plus 2 mg/kg xylazine to 16 mg/kg ketamine plus 8 mg/kg xylazine, mean 8 mg/kg ketamine plus 4 mg/kg xylazine, in wild bears. (J59.24.w1)
    • Initial intended dose 2.2 mg/kg xylazine plus 4.4 mg/kg ketamine in wild bears. (J1.25.w6)
  • Ursus arctos - Brown bear 
  • Ursus maritimus - Polar bear: 
    • For cubs of the year, effective doses were 1.6 - 5.0 mg (mean 2.8 mg/kg) each drug, with first effect after 1.0-3.0 minutes (mean 1.6 minutes) and immobilisation by 1.0 - 4.0 minutes (mean 1.3 minutes). (J1.17.w12)
    • For older bears, effective doses were 3.3 - 10.6 mg/kg (mean 6.8 mg/kg) each drug, with first effect after 1.0-10.0 minutes (mean 4.6 minutes) and induction by 4.0 - 30.0 minutes (mean 13.2 minutes). (J1.17.w12)
    • Bears were tractable (handleable) for a period of at least 30 minutes. (J1.17.w12)
    • In bears of at least one year old, doses of 4.1 - 30.8 mg/kg, median 11.0 mg/kg in one year, and 10.7 mg/kg in a second year. (J1.21.w7)
  • Melursus ursinus - Sloth bear: xylazine 1.4 - 2.44 mg/kg + ketamine 5.80-9.75 mg/kg. (J4.189.w11)
    • Induction (to sternal recumbency) took 2 - 25 minutes; ataxia and disorientation were noted prior to development of sternal recumbency. Immobilisation (lateral recumbency) occurred after 4-30 minutes. (J4.189.w11)
    • All bears showed moderate salivation; two vomited white, frothy liquid (food and water had been withheld for 24 hours prior to immobilisation). (J4.189.w11)
  • Ursus thibetanus - Asiatic black bear:
    • Xylazine 2 mg/kg estimated body mass plus ketamine 4 - 5 mg/kg estimated body bass for wild bears following capture in traps. The drugs were administered intramuscularly using a blowpipe. (J46.271.w1)
    • Xylazine 1 mg/kg plus ketamine 15 mg/kg in culvert-trapped bears, for handling and attaching radio-collars. The drugs were administered intramuscularly using a blowpipe. (J345.13.w6)

For further information see: Xylazine-Ketamine Anaesthesia in Bears

2) In combination with Tiletamine-Zolazepam (see: Xylazine-Tiletamine-Zolazepam Anaesthesia in Bears):

  • Ursus arctos - Brown bear
    • Xylazine 2.4-2.8 mg/kg plus tiletamine-zolazepam 3.6-4.2 mg/kg. (J345.14.w6)
  • Ursus maritimus - Polar bear:
    • Xylazine 2 mg/kg plus tiletamine-zolazepam 3 mg/kg (total drugs 5 mg/kg): 4.8 mg/kg in captive-held and 5.5 mg/kg total drugs in free-ranging wild polar bears. (J1.39.w5)

For further information see: Xylazine-Tiletamine-Zolazepam Anaesthesia in Bears

Lagomorphs - Oryctolagus cuniculus domesticus - Domestic rabbit:

  • 2.0 - 5.0 mg/kg intramuscularly or subcutaneously. (B546)
  • 1.0 -5.0 mg/kg subcutaneously or intramuscularly. (B602.41.w41)

Ferrets - Mustela putorius furo - Ferret:

  • 1 mg/kg subcutaneously or intramuscularly. (B602.41.w41)
  • 0.5 - 1.0 mg/kg subcutaneously or intramuscularly. (B631.22.w22)
    • Usually used with Ketamine 10 -20 mg/kg. Produces sedation; causes severe hypotension, bradycardia, and arrhythmias; it is not recommended for use in this species. Xylazine can be reversed using yohimbine 0.2 mg/kg intravenously or 0.5 mg/kg intramuscularly. (B631.22.w22)
  • Xylazine 2.0 mg/kg plus Butorphanol 0.2 mg/kg intramuscularly. Xylazine can be reversed using yohimbine 0.5 mg/kg intramuscularly. (J213.3.w1)
  • Ketamine 10 - 30 mg/kg plus xylazine 1 - 2 mg/kg intramuscularly. Xylazine can be reversed using yohimbine, 0.5 mg/kg intramuscularly. (J213.3.w1)
  • Tiletamine-Zolazepam 1.5 mg/kg plus xylazine 1.5 mg/kg intramuscularly. Can be combined in one syringe. Xylazine can be reversed using yohimbine 0.5 mg/kg intramuscularly. (J213.3.w1)
  • Tiletamine-Zolazepam 1.5 mg plus xylazine 1.5 mg/kg plus Butorphanol 0.2 mg/kg intramuscularly. Can be combined in one syringe. Xylazine can be reversed using yohimbine 0.5 mg/kg intramuscularly. (J213.3.w1)

Great Apes

  • 0.5 - 2.0 mg/kg intramuscularly. (B336.39.w39)
    • For chemical restraint, in combination with other agents. (B336.39.w39)
    • Reversal with Atipamezole 0.25 - 0.5 mg/kg intramuscularly or Yohimbine 0.125 - 0.25 mg/kg  (B336.39.w39)
  • Induction of anaesthesia:
    • Ketamine 1.0 mg/kg plus Xylazine 0.25 mg/kg plus Tiletamine-Zolazepam 1.25 mg/kg can be used for induction of anaesthesia in great apes. Oxygen should be supplied, plus additional inhalant anaesthetic agent as required. The anaesthetised individual should be monitored closely. (B336.39.w39)
  • Adult Pan troglodytes - Chimpanzee: 1.1 mg/kg intravenously or 2.2 mg/kg intramuscularly. (W768.Jun2012.w1)
    • Ketamine 15 - 20 mg/kg plus Xylazine 1.0 mg/kg intramuscularly. (W768.Jun2012.w1)


  • 1.0 - 2.2 mg/kg intramuscularly once with Ketamine. (B115.8.w4)
Monitoring parameters
  • Level of sedation/anaesthesia/analgesia. (B263)
  • Respiratory function. (B263)
  • Cardiovascular function. (B263)
  • Hydration status if polyuria develops. (B263)

Return to Top of Page

Withdrawal period / Withholding time
Notes "Residues in edible tissues, except for the injection site, liver, and kidney, are usually below 0.1 ppm by 10 hours after administration. The levels in all tissues are below 0.1 ppm by 72 hours after administration." (J234.2.w1)


  • "Cattle may be slaughtered for human consumption only after 14 days from the last treatment." (B266)
  • "Do not use in cows producing milk for human consumption." (B266)


  • In the USA xylazine is approved for use in dogs, cats and horses, and in various deer (Dama dama - Fallow Deer, Odocoileus hemionus - Mule deer, Cervus nippon - Sika Deer, Odocoileus virginianus - White-tailed deer and Cervus elaphus - Red deer (North American Elk)) It is not approved for use in food-producing animals. "The FDA is concerned about the potential carcinogenicity of xylazine now that the 2,6-dimethylaniline metabolite has been shown to be carcinogenic in rats." It was noted that "The toxicological studies of xylazine submitted to FDA to date are insufficient to allow a determination of its carcinogenic response." [1998](J289.21.w3)
  • "Not approved for any species to be consumed for food purposes." (B263)
  • "While xylazine is not approved for use in cattle in the USA, at labeled doses in Canada it reportedly has been assigned withdrawal times of 3 days for meat and 48 hours for milk. FARAD has reportedly suggested a withdrawal of 7 days for meat and 72 hours for milk for extra-label use in the USA." (B263)

Return to Top of Page

Toxic Information

Toxic effects of Pharmaceutical Products
Contraindications / Precautions
  • Contraindicated in individuals with active ventricular arrhythmias. (B263)
  • Contraindicated in individuals receiving adrenoceptor stimulants (such as epinephrine). (B201.6.w6, B263)
  • Use with extreme caution in individuals with pre-existing cardiac dysfunction, hypotension, shock, respiratory dysfunction, severe hepatic insufficiency, severe renal insufficiency, pre-existing seizure disorders, severe debility. (B263)
  • Not recommended for use in the last trimester of pregnancy (except at parturition), particularly in cattle, as it may induce premature parturition. (B201.6.w6, B263)
  • Caution in debilitated or elderly individuals due to the profound cardiovascular changes. (B201.6.w6)
  • Caution in individuals known/suspected to have pulmonary disease. (B201.6.w6)
  • In ruminants: 
    • Care in dosing: check concentration and dose carefully. (B266)
    • Not for use in individuals with dehydration, urinary tract obstruction or debility. (B263)
    • In cattle: with higher doses (0.2 - 0.3 mg/kg) the animal may remain drowsy for some time and it is recommended that the animal should be kept in the shade. (B266)
    • "In case of accidental overdosage leading to respiratory failure cold water douches and artificial respiration are indicated." (B266)
  • In horses:
    • Caution is required as individuals may kick following auditory or other stimulation.(B263)
    • Use with caution during the vasoconstrictive phase of laminitis (reduces digital blood flow for about eight hours after administration). (B263)
    • Use with caution in individuals with intestinal impaction as xylazine may inhibit gastrointestinal mobility. (B263)
  • In cats and dogs: contraindicated in individuals with gastrointestinal obstruction due to emetic effects. (B201.6.w6)
Adverse Effects / Side Effects / Warnings
  • In large animals: ataxia. (B263)
  • In bradycephalic dogs and in horses with upper airway disease: dyspnoea may be seen. (B263)
  • Cardiac arrhythmias, bradycardia, polyuria, hypoxaemia, transient hyperglycaemia. (B201.6.w6)
  • In horses: intraarterial injection may cause severe seizures and collapse. (B263)
  • Horses may still kick (accurately) in response to stimulation, particularly auditory. (B201.6.w6)
  • In cats and dogs: emesis generally occurs within 3-5 minutes (particularly in cats): do not induce further anaesthesia until at least 3-5 minutes after administration to avoid possible aspiration. (B263)
  • Cats and dogs: adverse effects may include muscle tremors, bradycardia with partial atrio-ventricular block, reduced respiratory rate, movement in response to sharp auditory stimuli. (B263)
  • Dogs: aerophagia may result in bloat; gaseous stomach distention may interfere with interpretation of radiographs. (B263)
  • Cats: increased urination may occur. (B263)
  • Horses: adverse effects may include muscle tremors, bradycardia with partial atrio-ventricular block, reduced respiratory rate, movement in response to sharp auditory stimuli, sweating, increased intracranial pressure, decreased mucociliary clearance rates. (B263)
    • Initial bradycardia and second degree heart block resolve after about 10 minutes. (B201.6.w6)
  • Cattle: adverse effects may include profuse salivation, ruminal atony, bloat (maintain in sternal recumbency to avoid tympany), regurgitation, hypothermia, diarrhoea, bradycardia, polyuria, premature parturition. (B201.6.w6, B263)
    • Pre-treatment with atropine may be used to alleviate hypersalivation and bradycardia. (B263)
Operator Warnings --
Overdose / Acute Toxicity
  • May cause cardiac arrhythmias, hypotension, profound CNS depression, profound respiratory depression, seizures. (B263)
    • Reversal with yohimbine, atipamezole or tolazoline has been suggested. (B263)
    • Mechanical respiratory support with respiratory stimulants such as doxapram for treatment of respiratory depression. (B263)

Return to Top of Page

Detailed Toxicological Information
Classification --
Acute Toxicity --
Chronic Toxicity --
Reproductive effects
  • Safety in first month of pregnancy "not established." (B201.6.w6)
Teratogenic effects --
Mutagenic effects --
Carcinogenic effects


Organ toxicity --
Bird Toxicity --
Aquatic organism activity --
Other organism toxicity --

Return to Top of Page

Nutrient Information

Nutritional Data
Sources --
Biological Use --
Recommended Daily Allowance / Recommended level in food --
Stability in food (Storage time) --
Interactions --

Return to Top of Page

External / Environmental Information

External / Environmental Uses
Use --
Formulation --
Application method --
Application Concentration --
Persistence of Effect / Frequency of Application --

Return to Top of Page

Sources in the Environment
Natural sources --
Human-associated sources --

Return to Top of Page

Effects on the Environment
Effects in the aquatic environment


Effects on land --

Return to Top of Page

Persistence in the Environment
Breakdown in soil and groundwater


Breakdown in water --
Breakdown in vegetation --

Return to Top of Page