II. Technique

  1. Injection Locations
    1. Shoulder (Deltoid Muscle)
      1. Preferred injection site for age over 3 years
    2. Outer thigh (Vastus lateralis Muscle)
      1. Preferred injection site in under age 3 years
    3. Upper, outer aspect of buttock (gluteal Muscle)
      1. Identify landmarks and avoid sciatic nerve at inferior medial aspect
  2. Intramuscular Injection Needle
    1. Needle gauge: 22-25
      1. Aqueous medications: 22 to 25 gauge
      2. Thick solutions: 21 to 23 gauge
    2. Needle length varies by injection site (see below)
      1. Needles are typically 1 to 1.5 inches in teens and adults
  3. Thigh Intramuscular Injection
    1. Adequate needle length
      1. Needle 1 inch: Infants and Toddlers (age <3 years)
      2. Needle 1 to 1.25 inches: Age 3-10 years old
      3. Needle 1 to 1.5 inches: Age 11-18 years old
  4. Shoulder Injection (Deltoid)
    1. Adequate needle length
      1. Needle 5/8 inch: Weight <130 lb (60 kg)
      2. Needle 5/8 to 1 inch: Child <10 years old
      3. Needle 1 inch: Weight 130-152 lb (60 kg)
      4. Needle 1 to 1.5 inch
        1. Women: Weight 152-200 lb (70-90 kg)
        2. Men: Weight 152-260 lb (70-118 kg)
      5. Needle 1.5 inch
        1. Women: Weight >200 lb (>90 kg)
        2. Men: Weight >260 lb (>118 kg)
    2. Injectors arms should be at same height as patient's Shoulder
      1. Ensures injection will enter skin at 90 degrees (perpendicular) with less risk of injury
    3. Injection site
      1. Inject at central, thickest region of deltoid, below bony Shoulder by 2 inches (or 2-3 finger breadths)
    4. Complications
      1. Soft Tissue Injury (e.g. tendon, ligament, bursa) if injection placed too high in Shoulder
      2. Shoulder Injury Related to Vaccine Administration (SIRVA)
        1. Bancsi (2019) Can Fam Physician 65(1): 40-2 [PubMed]

III. Precautions

  1. Allow medication dose to warm to room Temperature before infection (reduces pain)
  2. Patients should dispose of needles in sharps container (NOT the trash)
  3. Avoid frequent site reuse due to injection site fibrosis risk
    1. Rotate injection sites
  4. Injection should be at 90 degrees to skin surface
  5. Avoid rubbing injection area after injection
  6. Encourage use of limb after injection to prevent freezing symptoms from dissuse
    1. Injection in the dominant arm Shoulder may ensure greater use
    2. Cool compresses may be used to reduce discomfort after injection
      1. Consider ice to area for 10 min prior to injection
    3. Ibuprofen or Acetaminophen may be used for discomfort
      1. Avoid premedication as very weak data suggests Vaccines may be less effective after Analgesics

IV. Efficacy

  1. Many standard IM medication uses are no more effective than their oral counterparts
    1. Vitamin B12 Replacement
    2. Ketorolac (Toradol)
    3. Corticosteroids
    4. Ceftriaxone in cases of refractory Otitis Media or Urinary Tract Infections in children
    5. Shatsky (2009) Am Fam Physician 79(4):297-300 [PubMed]

V. Contraindications: Relative

VIII. References

  1. (2021) Presc Lett 28(12):70
  2. (2021) Presc Lett 28(3): 13-4

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