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Q: My child's flu fever dropped after taking Tamiflu but returned 40 hours later. Is this normal or a complication? Does a 14.5-hour dose gap matter?
- Myeongchan Kim
- 7 hours ago
- 3 min read
Medically reviewed by Sang Hyun Ahn, MD
Content edited by Myeongchan Kim, MD
This post is a dramatization of a question and answer session experienced by our actual medical reviewers. Please note that this content is for informational purposes only and does not constitute medical advice. Always consult with a qualified healthcare professional for any health concerns or before making any decisions related to your health or treatment.
Question:
My child was diagnosed with the flu and prescribed Tamiflu on Wednesday. The fever lasted until Thursday evening and then went down. They were completely fine for about 40 hours, but on Saturday evening, my child wanted to lie down, and their temperature spiked again to 38.3°C.
Is it normal for a flu fever to drop and then return, or could this be a complication? My child is currently playing well and doesn't seem lethargic. Should we go to the emergency room? Also, since this is our first time dealing with the flu, I accidentally waited 14.5 hours before giving the second dose of Tamiflu on the first day. Will this be a problem?
Answer:
It is completely understandable to be worried when a fever returns after 40 hours of being fever-free, especially about three days into taking Tamiflu.
Here is an overview of what you should know and how to proceed:
When to Visit the Emergency Room
If your child shows any of the following signs, visit the emergency room or an urgent care center right away:
• Difficulty breathing (e.g., wheezing, flaring nostrils, or the skin pulling in under the ribs).
• Extreme lethargy, poor eye contact, or lack of normal responsiveness.
• Signs of dehydration (e.g., no urination for over 8 hours, severely dry lips and tongue).
• Complaints of chest or severe abdominal pain.
• A fever of 39.5°C or higher that does not come down at all even after taking fever-reducing medications.
Since you mentioned your child is playing well and not lethargic, an immediate ER visit is likely unnecessary right now. If they continue to stay hydrated and act normally, you can wait and consult your pediatrician during regular clinic hours tomorrow.
Is a Returning Fever Normal with the Flu?
• Yes, it is relatively common for a fever to drop and then return around the 2nd or 3rd day, even with early Tamiflu treatment. This is often just part of the natural process as the body clears the virus.
• However, if the fever persists for more than 5 days, or if it returns after a few days accompanied by new symptoms like a worsening cough, it is important to have your child evaluated for secondary bacterial infections, such as an ear infection (otitis media) or pneumonia.
Does the 14.5-Hour Tamiflu Gap Matter?
• The recommended dosing interval for Tamiflu is every 12 hours. However, having a longer gap of 14.5 hours early in the treatment is not a major issue.
• As long as you have been giving the subsequent doses at the correct 12-hour intervals, the medication's overall effectiveness should not be significantly impacted. The returning fever is highly likely due to the natural course of the flu, rather than the delayed dose.
Home Care Guidelines for Tonight
• Administer fever-reducing medications (Acetaminophen or Ibuprofen) based on your child's weight if the fever is making them uncomfortable.
• Encourage frequent, small sips of fluids (water, electrolyte solutions, or warm broth) to prevent dehydration.
• Dress your child in light clothing and keep the room temperature comfortably cool.
• Continue to monitor their breathing, responsiveness, and overall condition.
Tonight, keep a close eye on your child for any of the warning signs mentioned above. Tomorrow, contact your pediatrician to schedule a follow-up appointment. You can ask them to check your child for any potential complications like an ear infection or pneumonia, and confirm the continued plan for the Tamiflu course.
For extra peace of mind and clear guidance when tracking your child's symptoms, the FeverCoach app is always there to help.
