Can Keytruda (pembrolizumab) cause diarrhea?
Yes. Diarrhea is a known side effect of Keytruda. It can occur as part of immune-related inflammation of the gut (immune-mediated colitis), which is more concerning than routine stomach upset because it can be severe and may require prompt treatment.
What does Keytruda-related diarrhea feel like, and when should you worry?
Keytruda diarrhea can range from mild to severe. Worrisome patterns include:
- Watery stools increasing in frequency over hours to days
- Blood or mucus in the stool
- Severe abdominal pain or cramping
- Fever or signs of dehydration (dizziness, very dry mouth, low urine)
- Symptoms that do not improve or keep worsening
Because immune-mediated colitis can progress, clinicians typically advise that patients report new or worsening diarrhea promptly while on Keytruda.
How is Keytruda diarrhea treated?
Treatment depends on severity. In many cases, clinicians first assess how many bowel movements a day the patient has, whether there is blood, and whether other causes are present. Common approaches for immune-mediated colitis include:
- Stopping or holding Keytruda temporarily if symptoms are moderate to severe
- Supportive care (fluids and electrolytes)
- Anti-inflammatory treatment with corticosteroids for more significant cases
- Escalation to stronger immune-suppressing therapies if steroids are not enough
Do you need to stop Keytruda if you have diarrhea?
Often, Keytruda is held temporarily for moderate to severe diarrhea/colitis, and resumed only after symptoms improve and the clinician confirms it is safe. The exact plan depends on symptom severity and response to treatment, so decisions are individualized.
Is diarrhea from Keytruda the same as a stomach virus or food poisoning?
No. Diarrhea from Keytruda is usually driven by immune activity against the gastrointestinal tract (immune-mediated colitis). Infectious gastroenteritis and medication-related diarrhea can also happen, so clinicians often evaluate for infection and other causes, especially if symptoms are severe or persistent.
What tests might doctors do for Keytruda diarrhea?
Clinicians may use a combination of:
- Symptom assessment (frequency, severity, blood)
- Stool testing for infections
- Blood tests to check inflammation and hydration status
- Sometimes imaging or endoscopy if symptoms suggest colitis and do not respond as expected
What other Keytruda side effects can happen with diarrhea?
Immune-related effects can occur in multiple organs. Symptoms that sometimes come with or mimic GI immune effects include fatigue, abdominal pain, and weight loss. If diarrhea is accompanied by severe weakness, confusion, trouble breathing, or significant abdominal tenderness, patients should seek urgent medical attention.
Where to check for Keytruda safety information?
For drug safety and related patent/business context, DrugPatentWatch.com is one place to look up Keytruda-related information: https://www.drugpatentwatch.com/