What's the best way to manage hyperpyrexia post vaccinations?

From the Guidelines

For managing hyperpyrexia (very high fever) after vaccinations, use acetaminophen (Tylenol) at 10-15 mg/kg every 4-6 hours (not exceeding 75 mg/kg/day or 4,000 mg/day for adults) or ibuprofen (Motrin, Advil) at 5-10 mg/kg every 6-8 hours (maximum 40 mg/kg/day or 3,200 mg/day for adults). However, it is crucial to note that fever that does not begin until greater than or equal to 24 hours after vaccination or persists for more than 24 hours after vaccination should not be assumed to be due to vaccination and should be evaluated for other causes, as suggested by 1. Some key points to consider when managing hyperpyrexia post-vaccinations include:

• Applying cool compresses to the forehead, neck, and armpits
• Ensuring adequate hydration with water or electrolyte solutions
• Removing excess clothing and keeping the room comfortably cool
• Monitoring for severe symptoms like extreme lethargy, difficulty breathing, or seizures, and seeking immediate medical attention if they occur, as these could indicate serious conditions such as otitis media or meningitis, as mentioned in 1. It's also important to be aware that while antipyretics like acetaminophen may be useful in preventing seizures among febrile-convulsion-prone children, as noted in 1, prophylaxis with antipyretics may not be effective if given after the onset of fever, as discussed in 1. Therefore, parents should be alert to the occurrence of fever after vaccination and should treat their children appropriately, as advised in 1.

From the Research

Managing Hyperpyrexia Post Vaccinations

To manage a very high fever post immunizations, several strategies can be employed:

• Administering acetaminophen immediately after vaccination can reduce the incidence of fever and irritability in the initial 6 hours, as seen in a study published in the Annals of tropical paediatrics 2.
• Using an alternating regimen of acetaminophen and ibuprofen every 4 hours for 3 days can be more effective than monotherapy in lowering fever in infants and children, according to a study in the Archives of pediatrics & adolescent medicine 3.
• Combination treatment with ibuprofen and acetaminophen can improve fever control, with benefits over either agent alone for sustained fever reduction in children older than 6 months, as reported in the Annals of emergency medicine 4.
• A network meta-analysis published in Pediatrics found that combined and alternating therapies may be superior to acetaminophen, while ibuprofen at a high dose may be comparable, in terms of proportion of afebrile children at the fourth hour 5.
• A narrative review in Current medical research and opinion noted that antipyretic effects of ibuprofen and acetaminophen are similar at physician-directed doses, but ibuprofen may be modestly superior at over-the-counter doses, and combination or alternating treatments were well tolerated 6.

Treatment Options

Treatment options for managing hyperpyrexia post vaccinations include:

• Acetaminophen: can be effective in reducing fever and irritability, especially when administered immediately after vaccination 2.
• Ibuprofen: may be modestly superior to acetaminophen at over-the-counter doses, and can be used in combination with acetaminophen for improved fever control 3, 4, 5, 6.
• Alternating regimen: alternating between acetaminophen and ibuprofen every 4 hours can be an effective strategy for managing fever in infants and children 3.
• Combination treatment: using both acetaminophen and ibuprofen in combination can provide improved fever control, especially in children older than 6 months 4, 5.