From the FDA Drug Label
The administration of promethazine HCl in 25-mg doses will control minor transfusion reactions of an allergic nature. The recommended dose of Avil (promethazine) for blood transfusion reaction in pediatrics is 25 mg.
- However, the dose should be adjusted to the smallest amount adequate to relieve symptoms.
- For children, the usual dose is 0.5 mg per pound of body weight. 1
From the Research
For a blood transfusion reaction in pediatric patients, the recommended dose of diphenhydramine (Avil/Benadryl) is 1 mg/kg/dose administered intravenously or intramuscularly, with a maximum single dose of 50 mg. This medication should be given immediately upon recognition of symptoms such as urticaria, pruritus, or other signs of a mild to moderate allergic transfusion reaction. The dose may be repeated every 6 hours as needed based on symptom persistence. When administering IV diphenhydramine, it should be given slowly over at least 5 minutes to avoid hypotension. In addition to diphenhydramine, management should include stopping the transfusion immediately, maintaining IV access with normal saline, and monitoring vital signs frequently. For severe reactions, additional interventions such as epinephrine, corticosteroids, or bronchodilators may be necessary. Diphenhydramine works by blocking histamine H1 receptors, thereby reducing the allergic response that occurs during transfusion reactions. It's essential to document the reaction and notify the blood bank to investigate the cause of the reaction, as emphasized in recent studies 2. Key considerations in pediatric patients include the higher incidence of allergic reactions compared to adults, as noted in studies such as 3, and the importance of selecting and processing RBC components appropriately to minimize the risk of transfusion reactions, as discussed in 4. However, the most recent and highest quality study 2 provides a comprehensive review of blood transfusion reactions, including management strategies, which supports the recommended dose of diphenhydramine for pediatric patients. Some key points to consider in the management of blood transfusion reactions in pediatric patients include:
- Stopping the transfusion immediately upon recognition of a reaction
- Maintaining IV access with normal saline
- Monitoring vital signs frequently
- Administering diphenhydramine as needed for allergic reactions
- Considering additional interventions such as epinephrine, corticosteroids, or bronchodilators for severe reactions
- Documenting the reaction and notifying the blood bank to investigate the cause.