What is the management for an injection site reaction?

Management of Injection Site Reactions

For injection site reactions, management should be based on severity, with mild to moderate reactions treated with cold compresses, antihistamines, and topical corticosteroids, while severe reactions require immediate medical attention including epinephrine administration for anaphylaxis. 1

Assessment and Classification

First, determine if the reaction represents:

1. Mild to moderate local reaction: Characterized by erythema, swelling, pruritus, and pain around the injection site
2. Severe reaction/anaphylaxis: Characterized by systemic symptoms affecting airway, breathing, circulation, or consciousness

Management Algorithm

For Mild to Moderate Local Reactions:

• Stop the administration of the medication if still being administered 1
• Apply cold compresses to reduce swelling and discomfort
• Administer antihistamines:
  • Combination of H1 and H2 antagonists is superior to either alone 1
  • Diphenhydramine 25-50 mg orally or IV
  • Ranitidine 50 mg IV (if needed)
• Consider topical corticosteroids for pruritus and inflammation
• Monitor vital signs until resolution 1

For Severe Reactions/Anaphylaxis:

1. Stop the administration of medication immediately 1
2. Maintain IV access 1
3. Assess ABCs (Airway, Breathing, Circulation) 1
4. Position the patient appropriately:
   • Trendelenburg position for hypotension
   • Sitting up for respiratory distress
   • Recovery position if unconscious 1
5. Administer epinephrine immediately if anaphylaxis criteria are met:
   • 0.01 mg/kg (1 mg/mL dilution) to maximum 0.5 mL intramuscularly into lateral thigh 1
   • Can be repeated every 5-15 minutes if needed 1
   • Important: Avoid injection into digits, hands, feet, or buttocks due to risk of tissue necrosis 2
6. Fluid resuscitation:
   • 1-2 liters normal saline at 5-10 mL/kg in first 5 minutes 1
   • Crystalloids or colloids in boluses of 20 mL/kg, followed by slow infusion 1
7. Administer antihistamines:
   • Diphenhydramine 50 mg IV plus ranitidine 50 mg IV 1
8. For bradycardia: Atropine 600 μg IV 1
9. For persistent hypotension:
   • Dopamine (400 mg in 500 mL of 5% dextrose) at 2-20 μg/kg/min 1
   • Alternative: Vasopressin 25 units in 250 mL (0.1 U/mL) at 0.01-0.04 U/min 1
10. For patients on beta-blockers: Glucagon 1-5 mg IV over 5 minutes 1
11. Consider corticosteroids to prevent biphasic reactions:
    • 1-2 mg/kg of IV methylprednisolone every 6 hours 1
12. Monitor vital signs until resolution and observe for 24 hours after severe reactions 1

Prevention Strategies

• Proper injection technique:
  • Rotate injection sites to prevent tissue necrosis 2
  • Inject into appropriate tissue (vastus lateralis muscle for IM injections) 2
  • Cleanse skin properly before injection 1
• Patient education and training on proper self-injection techniques 3
• Consider premedication for patients with history of reactions 1
• For biologics: Consider changing injection techniques if reactions occur 3

Important Caveats

• Injection site reactions are not necessarily correlated with drug efficacy or development of antidrug antibodies 3
• Misunderstanding the pathophysiology of injection site reactions may lead to unnecessary discontinuation of effective treatments 3
• Rechallenge after severe reactions (CTCAE grade 3 or higher) or true anaphylaxis should not be attempted 1
• Patients with heart disease, hyperthyroidism, Parkinson's disease, diabetes mellitus, or pheochromocytoma require special caution when administering epinephrine 2
• Some reactions may be due to excipients like polysorbates rather than the active drug 4

Documentation

Accurate documentation of injection site reactions should include:

• Pre-injection assessments
• Description and grading of the reaction
• Management approach used
• Patient response to interventions 1