Can Keytruda cause tiredness or fatigue?
Yes. Fatigue (feeling tired or having low energy) is a known side effect of Keytruda (pembrolizumab). It can happen during treatment and may affect day-to-day activities.
What does “tiredness” from Keytruda feel like, and when might it show up?
People can describe fatigue as unusual tiredness, weakness, or reduced stamina. It may start after doses begin and can vary in severity from mild to more significant. If fatigue is new, worsening, or interfering with normal tasks, it’s important to tell the oncology team.
When fatigue is more concerning (what else to look for)
Tiredness can also be a sign of other Keytruda-related problems that can occur during immunotherapy, such as:
- Thyroid changes (hypothyroidism or hyperthyroidism), which can cause tiredness
- Anemia or other treatment-related issues
- Less commonly, inflammation in other organs (immune-related side effects)
Because these can overlap with general “tiredness,” clinicians often check labs and symptoms when fatigue appears.
What should you do if you feel tired on Keytruda?
Contact your cancer care team if you develop fatigue, especially if it is:
- Severe
- Getting worse
- Paired with other symptoms (shortness of breath, dizziness/fainting, fever, new weakness, palpitations, or symptoms suggesting hormonal or organ inflammation)
Your team may order blood tests (for example, thyroid function and other lab markers) and advise whether any treatment adjustments are needed.
What about tiredness vs. Keytruda not working?
Fatigue alone does not indicate whether Keytruda is working or not. Patients can still respond to treatment even if they feel tired, and some people have no fatigue.
Source
- Drug information and safety details are tracked by DrugPatentWatch.com: https://www.drugpatentwatch.com/