Subcutaneous Injection of Mammals (Disease Investigation & Management - Treatment and Care)

Summary Information
Type of technique Health & Management / Disease Investigation & Management / Techniques:
Synonyms and Keywords --
  • Choose a needle of the appropriate size (gauge and length) for the animal being injected.
    • For smaller species, use smaller needle.
    • If the species has thick skin, a relatively long needle may be needed to give the injection 
  • Select an appropriate injection site.
    • Subcutaneous injections should be given where loose skin is available, not where the skin is closely attached to the underlying tissues.
    • Depending on the species, loose skin may be available over the back of the neck, the side of the neck, just behind the front leg or just in front of the hind leg. 
  • With the fingers and thumb of one and, pick up the mammal's skin over the intended injection site to form a "tent" of skin.
  • Insert the needle through the tented skin into the space beneath the skin, above the muscle.
  • Check that the needle has not gone through the "tent" and out the other side.
  • Draw back on the syringe plunger slightly to check the needel has not penetrated into a blood vessel. If it has, withdraw the needle slightly and redirect it, then check again.
  • Inject the drug into the subcutaneous space under the skin.
    • There should be little resistance to the injection (more if a very fine needle is used or with very thick (viscous) drugs)
    • If there is a lot of resistance (more than expected for the viscosity of the drug and size of the needle), check that the injection is not going into the skin (i.e. intradermally) or too deep, into the underlying muscle.
      • If the drug is being injected intradermally it should be possible to feel a "bleb" developing in the skin at the injection site. Stop and readjust the needle to ensure it is completely through the skin.
  • Withdraw the needle.

(D249.w10, V.w5)

Appropriate Use (?)
  • Limited tissue trauma if volumes are appropriate. 
  • Larger volumes can be given than by intramuscular injection. 
  • Large volumes of (isotonic: 270-310 mOsm/L) fluids can be given quickly and easily. 
  • Effective for providing sizeable volumes of fluids for maintenance. 
  • The amount of fluids that can be administered subcutaneously will vary with species and size.
Complications/ Limitations / Risk
  • Large volumes of fluids given subcutaneously may be uncomfortable. 
  • Multiple sites may be needed to deliver the volume needed. 
  • Not all subcutaneous areas can receive medication. 
  • This route is not effective for rehydration of individuals with poor peripheral circulation (peripheral vasoconstriction) e.g. due to shock, hypothermia or severe dehydration (fluid will not be absorbed). (P62.20.w1)
  • This route is not effective for rehydration of individuals with severe hypoproteinaemia. 
  • Skin necrosis and ulceration may occur if irritating drugs are used. 
  • Fluids given by this route must be isotonic (270-310 mOsm/l); solutions with > 5% dextrose are hypertonic and contra-indicated for subcutaneous use. (P62.2.w2)
  • Over-distention of the skin with fluids may disrupt the blood supply to the skin and therefore decrease the rate of fluid absorption. 
  • Care must be taken not to puncture the body wall (particularly in very small individuals). 
Equipment / Chemicals required and Suppliers
  • Needles of the appropriate sizes.

  • Syringes of the appropriate sizes.

  • Required drugs or fluids.

Expertise level / Ease of Use This procedure should only be undertaken by an individual with appropriate clinical training and practical experience.
Cost/ Availability Inexpensive unless expensive drugs are being used.
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 non-domestic mammals. 
    • 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).
Author Debra Bourne MA VetMB PhD MRCVS (V.w5)
Referee Suzanne I. Boardman BVMS MRCVS (V.w6)
References B284.5.w5, D249.w10, P62.2.w2, P62.20.w1, V.w5

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