TECHNIQUE

Medetomidine-Ketamine-Midazolam Anaesthesia in Bears  (Disease Investigation & Management - Treatment and Care)

Summary Information
Type of technique Health & Management / Disease Investigation & Management / Techniques:
Synonyms and Keywords See also:
Description Note: medetomidine doses are mainly given in microgrammes per kilogram bodyweight, indicated in the text below as "g/kg". Other drug doses are generally given in milligrams per kilogram bodyweight (mg/kg).

N.B. Information given in this page is to be used in conjunction with the relevant section on Bears in Treatment and Care - Anaesthesia and Chemical Restraint

Preparation for anaesthesia:

  • Whenever possible (with captive bears), the bear should be moved to a safe, quiet, well-controlled situation away from other bears. (B407.w18, D247.7.w7)
  • Avoid anaesthetising immediately after the bear has eaten, to reduce the risks associated with vomiting and regurgitation during induction, anaesthesia or recovery. (D156.w2)
    • Preferably starve for 24 hours before anaesthesia. (B407.w18)
    • Withhold water for eight hours and food for 24 hours before immobilization. (D247.7.w7)

Administration:

  • By intramuscular injection

Suggested doses:

During induction:

  • Induction took 12.1 +/- 2.12 minutes (range 9-15 minutes). (P507.2005.w7)

During anaesthesia:

  • Initial heat rates averaged 59 +/- 29 bpm (range 27-118 bpm). Initial oxygen saturation was 86.14 +/- 4.64 % (range 76-93%), rising with oxygen supplementation to over 90%. (P507.2005.w7)

Duration of anaesthesia:

Reversal with Atipamezole:

  • Atipamezole was given at 0.119 - 0.189 mg/kg, half administered intravenously and half administered intramuscularly. (P507.2005.w7)
  • Atipamezole, total dose five times the dose of medetomidine (5 mg atipamezole per 1 mg medetomidine), administered half intravenously and half intramuscularly. (D315.3.w3)

During recovery:

  • [No data available]
Appropriate Use (?)
  • This combination produced satisfactory anaesthesia in four bear species. (P507.2005.w7)
  • While similar to medetomidine-tiletamine-zolazepam, this combination has the advantage of the potential to alter the ratio between the dissociative anaesthetic (ketamine) and the benzodiazepine (midazolam). (P507.2005.w7)
  • This combination may be used to produce shorter recovery times than Medetomidine-Ketamine-Midazolam Anaesthesia in Bears. (P507.2005.w7)
    • The mean elimination half-life of 77 +/- 18 minutes of midazolam (in dogs) makes it a good choice for short procedures in carnivores. (P507.2005.w7)
Notes --
Complications/ Limitations / Risk [Limited information is available on the use of this anaesthetic combination in bears at this time.]
  • Physical injury, sometimes severe or even fatal, can occur when bears are darted. (P9.2004.w4, J40.32.w1, D249.w10)
Equipment / Chemicals required and Suppliers
Expertise level / Ease of Use
  • Bears are large, powerful carnivores. Anaesthesia of bears should be carried out by experienced personnel. (V.w6)
Cost/ Availability
  • Cost and availability of drugs required may vary between countries.
Legal and Ethical Considerations
  • In some countries there may be legislation restricting the use of this type of technique to licensed veterinarians. For example in the UK: "The Veterinary Surgeons Act 1966 (Section 19) provides, subject to a number of exceptions, that only registered members of the Royal College of Veterinary Surgeons may practice veterinary surgery." (see: LCofC1 - RCVS Guide to Professional Conduct 2000 - Treatment of Animals by Non-Veterinary Surgeons).).

Use of Drugs (Medication):

  • Many drugs are not registered for use in particular species and care should be taken in their use, with proper regard for possible toxic effects. Consideration should be give to relevant legislation regarding the use of drugs.
  • In any country, drugs are unlikely to be specifically licensed for use in bears. 
    • In Europe the prescription cascade must be followed, and the client's informed consent should be obtained, whenever a drug is used which is not licensed for use in a given species. (B284.5.w5)
    • In the UK, guidelines regarding the use of drugs are set out in the Royal College of Veterinary Surgeons Guide to Professional Conduct 2000: (see: LCofC1 - RCVS Guide to Professional Conduct 2000 - Choice of Medicinal Products).
    • In the USA, the Food and Drug Administration (FDA) regulates specific conditions for the use of drugs in animals and people. The Animal Medicinal Use Clarification Act of 1996 allows extra-label use of approved animal and human drugs under certain conditions, with extra-label use being allowed "in non-food-producing animals if the drug is approved by the FDA, is used by or on order of a licenced veterinarian, and there is a valid veterinarian/client/patient relationship." In food-producing animals (including game wildlife species), additional conditions for extra-label use include that there is no approved alternative drug for such use (or if there is, it is clinically ineffective), the veterinarian has established a substantially extended withdrawal period; the treated animal can be individually identified (e.g. with an ear tag or a collar) and assigned withdrawal times can be assured, ensuring no illegal residues. (B486.11.w11)
  • Additionally, many drugs used for immobilisation are controlled substances in many countries, and appropriate registration/licences, records etc. for the country in which the drugs are being obtained/used must be followed.

Use of remote injection systems

  • In some countries a firearms licence may be required for use of remote injection equipment.
    • e.g. in the UK, anyone possessing a blow-pipe, dart-gun etc. which can be used to discharge tranquillising drugs (i.e. for remote injection), must be authorised by a Firearms Certificate. This is issued by the police. (B284.5.w5)
Author Debra Bourne MA VetMB PhD MRCVS (V.w5)
Referee Suzanne I Boardman BVMS MRCVS (V.w6)
References B284.5.w5, B407.w18, B486.11.w11, D156.w2, D247.7.w7, P507.2005.w7, V.w6 

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