What are the premedications to prevent transfusion reactions?

Premedications to Prevent Transfusion Reactions

Acetaminophen and diphenhydramine should be administered 30-60 minutes before blood transfusion to prevent infusion reactions related to blood products. 1

Standard Premedication Protocol

• Acetaminophen (oral or IV) should be given 30-60 minutes before transfusion to prevent febrile reactions 1
• Diphenhydramine or other H1-histamine antagonist should be administered 30-60 minutes before transfusion to prevent allergic reactions 1
• Corticosteroids should NOT be routinely used for pre-medication before standard blood transfusions, as they can be lymphocytotoxic and may affect therapeutic outcomes 1

Monitoring During Transfusion

• Vital signs should be monitored before the start of transfusion (within 60 minutes), 15 minutes after the start of each unit, and within 60 minutes of the end of transfusion 1
• Respiratory rate monitoring is particularly important as dyspnea and tachypnea are typical early symptoms of serious transfusion reactions 1
• Patients should be instructed to report symptoms such as shortness of breath, rash, chills, chest pain, and back pain immediately 1

Management of Transfusion Reactions

For Mild to Moderate Reactions:

• Stop the transfusion immediately 1
• Switch to hydration fluid to keep the vein open 1
• Monitor for at least 15 minutes until resolution of symptoms 1
• For febrile reactions: administer IV paracetamol (acetaminophen) 1
• For allergic reactions: administer a second-generation antihistamine (loratadine 10 mg orally or cetirizine 10 mg IV/oral) 1
• Avoid first-generation antihistamines like diphenhydramine for treating reactions (despite using them for prevention) as they can exacerbate hypotension 1

For Severe Reactions:

• Stop the transfusion immediately 1
• Call emergency services or resuscitation team 1
• For anaphylaxis: administer epinephrine 0.3 mg IM into the anterolateral mid-third portion of the thigh 1
• Consider β2 agonist nebulizer (albuterol) for respiratory symptoms 1
• For hypotension: recline patient and administer NS bolus of 1000-2000 mL 1

Special Considerations

• Patients with a history of multiple transfusion reactions may benefit from washed blood products 2
• Patients at high risk for transfusion-associated circulatory overload (TACO) should receive slow transfusion, close monitoring, and possibly prophylactic diuretics 1
• Risk factors for TACO include older age (>70 years), heart failure, renal failure, hypoalbuminemia, and low body weight 1
• Premedication may be more beneficial for platelet transfusions or in patients with hematological diseases 2

Evidence on Effectiveness

• The evidence for routine premedication is mixed, with some studies showing no significant difference in overall reaction rates between premedicated and non-premedicated patients 3, 4
• However, analysis of specific reaction types has revealed a significant decrease in the risk of febrile reactions when pretransfusion medication is used with leukoreduced blood products 3
• Despite limited evidence, premedication remains standard practice in many institutions due to the potential serious consequences of transfusion reactions and the relatively low risk of acetaminophen and diphenhydramine 2

Common Pitfalls to Avoid

• Do not use corticosteroids routinely as premedication for standard transfusions 1
• Avoid administering first-generation antihistamines (diphenhydramine) to treat reactions as they may exacerbate hypotension and cause sedation 1
• Do not continue transfusion if a reaction is suspected; stop immediately and evaluate 1
• Do not neglect monitoring respiratory rate, as respiratory symptoms are often the earliest sign of serious reactions 1
• Remember that transfusion-associated circulatory overload (TACO) is now the most common cause of transfusion-related mortality and major morbidity 1