Medication, fever and chemotherapy

Here are some of the instructions I received during chemotherapy:

  • If you haven’t already done so, get a thermometer.
  • If the body temperature reaches:
    • 38 °C (100.4 °F): check again 1 hour later;
      • If the temperature has remained stable or increased, go to the emergency room;
      • if the temperature has decreased, it is correct.
    • 38,3 °C (100.94 °F) and more: you must go directly to the emergency room.
  • Never take a pain medication on your own without first checking whether you have a fever or not.

Why these instructions?

Because throughout the whole period of chemotherapy treatment, the immune system is weakened and it is very important to know whether or not you have a fever because it can be a sign that you have an infection.

Why be careful with analgesics ?

Because acetylsalicylic acid (Aspirin), acetaminophen or paracetamol (Tylenol or Doliprane) and ibuprofen (Advil, Motrin), as well as other similar drugs, can mask or lower fever.

But without fever, one may think that it is not as serious and/or dangerous as it is and the infection can then continue to progress.

A concrete example

Setting the scene

In the last days of April and the first week of May, I was sick with the flu: nasal congestion, extreme fatigue, slight headache, aches and pains, sore throat, coughing and chills. Were chills caused by fever? Maybe, but according to my thermometer, I didn’t have a fever.


My thermometer indicated that my temperature was normal except that I take a combination of painkillers on a daily basis, including acetaminophen, under medical supervision… This may have masked the fever and lessened headache and aches and pains. This is all the more likely because the chills lasted 3-4 days and the fever normally disappears on its own after 3 or 4 days, according to my family doctor…

Is it serious that I don’t know for sure if I have a fever or not? No. Why? Because I had a multitude of other symptoms that informed me that my body was fighting something. In addition, I am not in chemotherapy and I have had only hormone therapy since November 2014. If I had been on chemotherapy, I would have gone to the ER.

Morale of the story

The instructions mentioned at the beginning are excellent. However, I would add one for people in chemotherapy :
If you have reason to believe that you may have a fever but your thermometer says no, go to a health care professional for advice or, at the very least, talk to a health care professional.

It’s better to be too careful than not enough…


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