Chemicals / Complex Chemical Agents/ Chemical:

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




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-antagonist used primarily for reversal of medetomidine. (B263)

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Names and Formulae
Type Alpha-2 adrenergic antagonist. (B263
Alternative Names Atipamezole Hydrochloride (Atipamezole HCl), Antisedan (Pfizer). (B263, B201.6.w6, B266
Chemical Formula C14H16N2. (W324)
Chemical Structure --
Molecular Weight 212.2938. (W324)
Related Chemicals --

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Physical Properties / Chemistry


Melting point --
Boiling point --
Density --
Water solubility --
Other solubility --
Acid/Base --

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Pharmacology & General Information
  • Competitive inhibitor of alpha2-adrenergic receptors. (B263)
  • Effects: reversal of alpha2-agonist activity, decreased blood pressure, increased heart rate, increased respiratory rate, reduced analgesic effect of alpha2-agonists.(B263)
Storage / Stability
  • Store at room temperature (15-30C); protect from light. (B263)
Legal Category (In UK) POM (B266)

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Associated Techniques




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

Authors Debra Bourne (V.w5); Penny Cusdin (V.w60)
Referees Suzanne I. Boardman (V.w6)

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Therapeutic Information

Appropriate Use
  • Some relapse into sedation has been seen in cattle following use to reverse the effects of xylazine and medetomidine. (B205.12.w12)
  • --

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Pharmacokinetics and Drug Interactions
Absorption /Bioavailability
Distribution --
Plasma Protein binding / Storage --
Elimination Route
  • Metabolised in the liver. (B263)
  • Metabolites are eliminated in urine. (B263)
Elimination half-life / Clearance Rate
Drug Interactions
  • Lack of data: caution should be applied if using with any drug other than medetomidine (B263)

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Formulations available
  • Antisedan (Pfizer): Clear, colourless solution containing atipamezole hydrochloride 5 mg/mL, with methylparahydroxybenzoate PhEur 1 mg/mL as an antimicrobial preservative. (B266)
Doses / Administration Routes / Frequencies For intramuscular injection. (B266)
  • In dogs: The optimal dose in g/kg is five times the dose of medetomidine; this is a volume of Antisedan (Pfizer) equal to the volume of Domitor (Pfizer) given previously). (B266)
  • In cats: The optimal dose in g/kg is 2.5 times the dose of medetomidine; this is a volume of Antisedan (Pfizer) equal to half the volume of Domitor (Pfizer) given previously). (B266)
  • In horses: (outwith the data sheet) 150 g/kg. (B201.6.w6)
  • In cows: 25 or 50 g/kg atipamezole, intramuscularly or intravenously, will reverse the effects of xylazine given at a dose of 0.2 mg/kg, and restore normal ruminal motility. If given intravenously, some relapse may be seen two hours later, but not enough to cause recumbency. A dose of 60 g/kg atipamezole given either intravenously, or half intravenously and half intramuscularly, in calves results in a rapid smooth reversal of medetomidine with recovery to ambulation. (B205.12.w12)

Erinaceus europaeus - West European Hedgehog:


The following information is taken with permission directly from the Elephant Care International website (W580.Aug2005.w6):

a) 1 mg atipamezole for every 8-12 mg xylazine will result in quick reversal in Asian elephants (Cheeran, 2002).

b) 5-10 mg atipamezole injected IM or slow IV will reverse 100 mg xylazine (Rietschel 2001).

c) 8-14 g/kg atipamezole was given to partially reverse xylazine (33-72 g/kg) 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 (Honeyman 1998).

d) Atipamezole effectively reverses medetomidine sedation at doses of 200 mcg/kg body weight. Note that this is a general (i.e. not elephant specific dose). (Lance, 1991).

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) 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

c) Honeyman,V.L., Cooper, R.M., 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

d) Lance,W.R. 1991. New pharmaceutical tools for the 1990's. Proceedings of the American Association of Zoo Veterinarians 354-359

Bears (Ursidae - Bears (Family))

Lagomorphs - Oryctolagus cuniculus domesticus - Domestic rabbit:

  • 1 mg/kg, subcutaneously, intramuscularly, intraperitoneally or intravenously. (B373.Guide.w41)
  • 1 mg/kg, subcutaneously, intravenously or intramuscularly. For the reversal of medetomidine. (B600.5.w5)
  • 1 mg/kg by intramuscular, intraperitoneal or subcutaneous injection. (B546)
  • The same volume as the volume of medetomidine used, subcutaneously, intraperitoneally or intravenously. (B602.41.w41, B548.w8)

Ferrets - Mustela putorius furo - Ferret:

  • 1 mg/kg subcutaneously, intramuscularly or intravenously. (B602.41.w41)
  • 0.05 - 0.1 mL subcutaneously or intramuscularly. To reverse Medetomidine. (B626.App.w22)
  • 0.4 - 1.0 mg/kg subcutaneously, intramuscularly or intravenously - the same volume as the medetomidine given. (B631.22.w22)

Great Apes

Monitoring parameters

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Withdrawal period / Withholding time
Notes --

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Toxic Information

Toxic effects of Pharmaceutical Products
Contraindications / Precautions
  • Not recommended for use in pregnant or lactating animals as its safety in such individuals has not been established. (B263)
Adverse Effects / Side Effects / Warnings
  • Occasional adverse effects may include vomiting, defecation, diarrhoea, hypersalivation, panting, tremors, brief excitation or brief apprehensiveness. (B263, B201.6.w6)
  • High dosage may cause transient over-alertness and tachycardia. (B201.6.w6)
  • Care following administration: reversal may be rapid and individuals emerging from sedation/analgesia may show behaviour which is apprehensive or aggressive. (B263)
  • Administration may cause short-term hypotension. (B201.6.w6)
  • Consider administration of analgesics such as butorphanol, particularly after painful procedures. (B263)
Operator Warnings --
Overdose / Acute Toxicity
  • In dogs: overdoses of ten times normal dose were tolerated "without major effects." Dose-related effects included: panting, excitement, trembling, vomiting, soft/liquid faeces, scleral vasodilatation, muscle injury at the injection site. (B263)

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Detailed Toxicological Information
Classification --
Acute Toxicity --
Chronic Toxicity --
Reproductive effects --
Teratogenic effects --
Mutagenic effects --
Carcinogenic effects


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

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Nutrient Information

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

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External / Environmental Information

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

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

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Effects on the Environment
Effects in the aquatic environment


Effects on land --

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Persistence in the Environment
Breakdown in soil and groundwater


Breakdown in water --
Breakdown in vegetation --

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