How to Give Medications to Dogs
Injections
Injecting any foreign substance into the body always carries with it the danger of causing an acute allergic or anaphylactic reaction. Treating anaphylactic shock requires immediate intravenous adrenaline and oxygen. This is one reason why it is best to have your veterinarian give injections. As a precaution, do not administer a drug by injection to a dog who has had any sort of past history of an allergic reaction (such as hives) to that drug.
If it becomes necessary to give injections at home (for example, if the dog is diabetic), have your veterinarian demonstrate the procedure. Some injections are given under the skin (subcutaneous) and others into the muscle (intramuscular). Directions that come with the product will indicate the correct route of injection.
The injection itself usually is not painful, although intramuscular injections may hurt somewhat as the medicine is injected. Dogs should be restrained. Having an assistant is helpful.
Begin by drawing the medicine up into the syringe. If there is an air bubble inside, flick the syringe to get the bubble to the top. Then point the needle toward the ceiling or into a sink and press the plunger to expel all air from the syringe and needle. Make sure the correct amount is still in the syringe after the air bubble is expelled. Select the injection site, part the hair, and cleanse the dog’s skin with cotton soaked in alcohol.
WebMD Veterinary Reference from "Dog Owner's Home Veterinary Handbook"

