
Overview
This module describes how to inject medication into a patient’s muscle.
Indications
Administering intramuscular medication or vaccines
Contraindications
Damaged, infected, swollen, thickened, or scarred skin at the injection site
Some medications or vaccines may have their own contraindications
Patient information & consent
Always verify your patient’s identity and obtain informed consent before proceeding.
How do I explain this procedure?
“I need to give you an injection into your muscle.”
What can my patient expect?
“This will sting for a moment.”
What is my patient’s role?
“Keep still while I give the injection. Let me know if you have any allergies. Fearing needles is normal, but tell me if you have fainted from it. ”
Preparation

Documentation
Prescription chart or vaccine card as required
Equipment
Non-sterile gloves
only if indicatedonly if indicatedGloves are only necessary when there is a risk of exposure to body fluids or infection, such as for patients with broken skin or where contact precautions are indicated.
Alcohol-based hand rub
- Sharps containerSharps container
If a sharps container is not within arm's length, use a kidney dish or other hard container to temporarily hold used sharps and to carry them to the sharps container for disposal.
One blunt fill needle for aspiration and one
20-27 G needle for injection20-27 G needle for injectionThe size and length of needle depends on the type of solution to be injected, adipose tissue and muscular tissue and the age of the patient. Generally, for adults use 20-23 G (blue, black, green, yellow) and for children 25-27 G (brown, orange, blue).
- SyringeSyringe
some medication/vaccines are available in pre-filled syringes.
(size twice the volume of the dose of medication)
Medication or vaccine
Alcohol swab
Cotton wool ball
Site & Positioning
Ventrogluteal
This site on the lateral aspect of the buttock is the safest site to use. Position the patient lying on their stomach or side. To locate the site, use your right hand for the left hip or your left hand for the right hip. Place the heel of your hand on the greater trochanter, point the index finger to the anterior superior iliac spine, and the middle finger to the iliac crest. The area between the index and middle fingers is the ventrogluteal site.

Vastus Lateralis
This site is preferred for infants and toddlers. The vastus lateralis muscle runs along the anterolateral thigh. Inject into the outer middle third of the thigh. Position the patient sitting or lying with the leg slightly flexed.

Deltoid
Find the acromion process by palpating the bony prominence. The injection site is in the middle of the muscle, two to three fingerbreadths below this bony prominence.

Procedure
Follow medical asepsis without gloves.
Perform hand hygiene. Do not routinely glove unless indicated.
Check patient identity, allergies, consent, and that you have the correct, unexpired medication (
5 Rs5 RsRight patient
Right drug
Right dose
Right site
Right timingof medication administration).
Draw up the medication with the aspiration needle. Attach the injection needle to the syringe.
Select the injection site and expose; avoid recently used sites.
Clean the site with an alcohol swab (unless giving a vaccine). Allow to dry.
Use your non-dominant thumb and index finger to press down on the site, stretching the skin slightly.
Insert the needle at a 90° angle in a dart-like action, aiming to enter the muscle.
If using the recommended sites, intravascular injection is unlikely and aspiration is unnecessary; however, follow your institutional guidelines regarding aspiration.
Inject slowly over 10-30 seconds.
Wait 10 more seconds, then withdraw. Do not massage the site. Apply gentle pressure with a cotton ball.
Dispose of medical waste safely.
Record medication administration and the site you used. Monitor for any drug or injection reactions.
Troubleshooting
I aspirated blood when pulling back on the plunger.
Pull back the needle and aspirate again to make sure you are not in a blood vessel before injecting the solution or select another site. Injecting a drug into a blood vessel may damage the vessel or the drug may not be suitable for IV administration and cause serious complications.
The medication is leaking out of the injection site.
Next time, try using the Z-track method. Use your non-dominant hand to pull the skin sideways. Enter and inject while still pulling sideways. After withdrawing, release the skin.
Risks
Bleeding, bruising, and pain at the site
Infection or irritation at the site, including forming an abscess
Drug-related complications, including anaphylaxis
Sharps injury to healthcare personnel
Vasovagal response (fainting)
References
West H. Injections. In: Dehn R, Asprey D, eds. Essential Clinical Procedures. 3rd ed. Philadelphia: Elsevier; 2013.
WHO Best Practices for Injections and Related Procedures Toolkit. World Health Organization: Geneva; 2010.
Chippewa Valley Technical College. Administering Intramuscular Medications. In: Nursing Skills. Available from: https://wtcs.pressbooks.pub/nursingskills/.
Joubert A. Administration of injections. In: Mulder M, Joubert A, Olivier N, eds. Practical Guide for General Nursing Sciences. 2nd ed. Pearson; 2020.