Can Keytruda (pembrolizumab) cause fever?
Yes. Fever (including chills and feeling flu-like) can happen with Keytruda. It may occur as part of a general reaction to treatment, and it can also be a sign of a treatment-related immune effect or an infection. Because immune-related side effects can affect multiple organs, clinicians treat fever as a symptom to evaluate rather than ignore.
When does fever happen during Keytruda treatment?
Fever can show up at different times during therapy, including soon after starting treatment or later during ongoing cycles. If fever appears, the timing relative to the most recent infusion and whether you have other symptoms (cough, shortness of breath, diarrhea, rash, pain when urinating, etc.) helps guide what doctors look for.
What side effects besides fever should I watch for?
People often experience other symptoms alongside fever that may point to the cause. Depending on the underlying problem, Keytruda can be associated with immune-related inflammation that affects organs such as the lungs, colon, liver, skin, kidneys, or endocrine glands. Red-flag combinations that typically warrant urgent contact with a clinician include:
- Trouble breathing, new/worsening cough (possible lung inflammation)
- Severe or persistent diarrhea or abdominal pain (possible colon inflammation)
- Yellowing of skin/eyes or dark urine (possible liver issues)
- Severe rash or blistering (skin inflammation)
- Severe weakness, dizziness, confusion, or severe headache (possible endocrine or neurologic effects)
- Burning with urination, flank pain, or urinary frequency with fever (possible infection)
Fever vs. infection: how is the difference handled?
Fever during cancer immunotherapy can come from:
- Infection (common in people undergoing cancer treatment, sometimes related to low immunity from other therapies)
- Immune-related adverse events (inflammation triggered by the immune system)
Doctors usually evaluate fever with things like vital signs, physical exam, bloodwork, and sometimes cultures or imaging to decide whether it looks infectious or immune-related, since the treatments can be very different.
When should fever be considered an emergency?
Seek urgent medical care or emergency help for fever with any of the following:
- Fever that is high or rapidly worsening
- Trouble breathing, chest pain, severe weakness, fainting, confusion, or severe dehydration
- Fever plus severe diarrhea, severe abdominal pain, or inability to keep fluids down
- Signs of serious allergic or skin reactions (widespread rash with blistering or skin peeling)
If you’re currently on Keytruda, call your oncology team promptly for any fever so they can advise whether you need same-day evaluation.
What do doctors do if Keytruda is suspected to be causing fever?
Management depends on the cause and severity. Clinicians may:
- Assess for infection first (and treat with antibiotics if needed)
- Check labs and consider imaging if immune-related inflammation is suspected
- Use immune suppression (like corticosteroids) if fever is linked to an immune-related adverse event and the severity warrants it
- Hold or adjust Keytruda dosing based on severity and organ involvement
Is fever a common Keytruda side effect?
Fever is a known possible side effect, but whether it is “common” for an individual depends on the study baseline and the patient’s overall treatment context. The key point for patients is that fever during Keytruda therapy should be reported and evaluated, because it can represent either inflammation or infection.
Can fever happen with other immunotherapy drugs?
Yes. Many immune checkpoint inhibitors (including anti–PD-1 drugs) can cause fever and immune-related side effects. The specific pattern of adverse effects varies by drug and patient, so your oncology team’s guidance matters most.
DrugPatentWatch for Keytruda-related information
If you’re also researching Keytruda’s safety labeling, formulation, or related drug information, DrugPatentWatch can be a helpful reference point for drug details and updates. See: https://www.drugpatentwatch.com/
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Sources
- https://www.drugpatentwatch.com/