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Keytruda and Diarrhea: What Users Say

Diarrhea: mentioned by 12 users (4.8%)

Based on user experiences from 249 Keytruda reviews, the following table shows the most commonly mentioned side effects.

All user comments are moderated by Drugs.com. Each review is verified for relevance and screened for inappropriate content. Side effects are user-reported and not clinically verified.

fatigue 12.0%
pain 6.8%
shortness of breath 6.4%
weakness 6.0%
loss of appetite 5.2%
tiredness 5.2%
diarrhea 4.8%
itching 4.0%
cough 3.2%
swelling 3.2%

Reviews for Keytruda

Commonly mentioned side effects
  • Blu...
  • Taken for less than 1 month
  • January 10, 2022

For Renal Cell Carcinoma "My mom was diagnosed with kidney cancer that spread to her lungs. My mom was talking, walking, aside from the cancer, nothing physically was wrong with her. When she had her first treatment of Keytruda, she started experiencing coughing up blood, severe diarrhea, it got so bad to the point she ended up in ICU, unable to walk or talk, and eventually she ended up passing away. This drug does not help, it only speeds up the death process."

1 / 10
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  • Bar...
  • Taken for 1 to 6 months
  • May 24, 2022

"My husband went through 2 different sets of 7-week treatments of radiation for angiosarcoma and never had any side effects to speak of at all. Then a spot came up again on his head, so they put him on Keytruda infusions. He had 2 treatments 6 weeks apart. He got really sick the week before his next one was scheduled, so they postponed it. He slept the whole next 6 weeks, stopped eating, barely drinking, so weak he could barely walk and then stopped being able to move on his own, he was confused, and most days could barely talk. The only side effect we were told he would probably might have was diarrhea, which he was more constipated than anything. After 6 weeks, 7 doctors, 1 ER visit, he died at home. No one was ever able to help him even when we told everyone he was on Keytruda. I have no doubt that medicine killed my husband and now I live with the memories of watching him die, and no one was able to help him. Please don’t take this drug."

1 / 10
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11 Report
  • Ros...
  • Taken for 1 to 6 months
  • June 9, 2022

For Renal Cell Carcinoma "Going for my third infusion in a few weeks and a cystoscopy. I get the infusion every six weeks. So far, just minor complaints, weight gain, rash that comes and goes, cough, some diarrhea, muscle pain sometimes, and face a little puffy. Bloodwork has been good so far. Had a TIA a month ago, but the oncologist said it wasn't the Keytruda. I'm going to my primary care this week to see what's going on. Not sure how to rate Keytruda yet, so I'll give it a 5."

5 / 10
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10 Report

Frequently asked questions

  • HBN...
  • Taken for less than 1 month
  • January 11, 2022

For Melanoma "My grandmother was diagnosed with nodular melanoma (without metastasis). Her oncologist suggested trying Keytruda. She died after two doses! Before starting immunotherapy, she was fine and very active. Side effects: weakness, muscle pain, weight loss, fatigue, dropping eyelids, dysphagia, breathing difficulty, severe diarrhea. I would not recommend this drug based on our experience!"

1 / 10
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  • Nan...
  • Taken for 1 to 6 months
  • September 10, 2021

For Urothelial Carcinoma "My husband started Keytruda for recurrent bladder cancer stage 4 in January '21. Oncologist said probably won't see side effects for weeks - not so. Next day he started with terrible arthritic pain, dizziness, fatigue, stiff neck, nauseated, unsteadiness in walking. This persisted, and then they gave him steroids. The steroids helped a little, but not much. Took treatment until May '21 and had 'numerous blood clots' in his lungs. 3 days in ICU with infusion to break up the blood clots caused from this horrible drug. Now on heavy blood thinners, has had diarrhea for 8 weeks and oncologist has sent us to a gastrologist. He's also suffering from severe neck issues as his neck droops - another side effect of this terrible drug. He's worse now than when he went through chemotherapy and they removed his bladder. This has been a horrible drug from the get-go - DO NOT USE IT!! PLEASE! It's not worth it..."

1 / 10
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  • pau...
  • Taken for 1 to 6 months
  • October 26, 2020

For Melanoma, Metastatic "Stage 3C melanoma, tumor was removed with lymph nodes and put on Keytruda. After each treatment, I've had side effects: diarrhea. After the 2nd treatment, the lymph nodes in my lungs were enlarged and made it very difficult to breathe. I should have gone to the hospital, along with the dizziness, confusion, loss of memory. My thyroid got way out of whack. I have been put on steroids, and the Keytruda has been put on hold. So far, it has been VERY difficult. This shows that the side effects are different for each person."

3 / 10
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7 Report
  • Sha...
  • October 3, 2022

For Non Small Cell Lung Cancer "Stage 4. I went for my first dose, got the IV, but my sodium was 120. They sent me to the ER with the IV. 4 days and now, 4 sodium pills later, it’s almost normal. First dose after, I had to stop because of diarrhea. 5 months later, a CT scan showed much regression in the tumors. Started again, been getting it every two weeks. 4 treatments ago, I broke out in hives. Next dose, no reaction, next dose landed me in the ER with anaphylactic shock. Stopped for 4 weeks. Restarting with pre-treatment. No problems. I have horrible fatigue, but I have MS also, and it’s fatiguing. A couple of spots of rough skin around my lips and a few white spots in my mouth. But in for more treatments, it’s been 18 months and still going, slower but better."

8 / 10
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More FAQ

  • Roc...
  • Taken for 1 to 6 months
  • September 11, 2022

For Melanoma, Metastatic "Be careful what the doctors and PAs don’t tell you, even when you ask. A close friend's wife took Keytruda. He tried to warn me that the danger zone for this drug is between the 6th and 9th treatment. I could not imagine it could be as bad as he told me, and I was wrong! Six days after my 6th infusion, the diarrhea started. It was like nothing I have had before. I won’t even attempt to describe it. It is now 2 weeks and 3 days, and the clinic is more concerned about the infusion money that they will no longer get, as I have quit this drug! Your quality of life sinks to a new low on this drug. I encourage the doctors and PAs to be honest with patients. Do not tell patients that different people react to drugs differently. That is a cop-out! This is a bad drug with serious side effects!"

2 / 10
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3 Report
  • Bil...
  • Taken for 6 months to 1 year
  • March 19, 2025

For Non Small Cell Lung Cancer "If I could do it over again, I would refuse to take Keytruda. Months after finishing, I am still suffering from side effects, and no one seems to have any ideas on how to stop the almost constant diarrhea. I have taken Imodium, but it doesn't help."

4 / 10
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  • Nic...
  • Taken for less than 1 month
  • December 7, 2018

For Non Small Cell Lung Cancer "It gave me extreme diarrhea and terrible stomach pain. If I could go back and not take this medication, I would. I discontinued it after 30 days."

2 / 10
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20 Report
  • Joh...
  • Taken for 6 months to 1 year
  • August 25, 2024

For Non Small Cell Lung Cancer "Very good so far. Almost a year, and only now a loose stool. Not had too bad a time, some sleepiness, dizziness, fatigue."

10 / 10
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3 Report
  • Kat...
  • Taken for 6 months to 1 year
  • September 5, 2024

For Non Small Cell Lung Cancer "Skin very, very dry. Sores in mouth (lasted only a short time). Neuropathy in feet and fingertips. Constipation/diarrhea. The neuropathy is the only one I can’t stand."

9 / 10
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Reviews may be edited to correct grammar/spelling or remove inappropriate content. Reviews appearing to come from parties with a vested interest are not published. This information is not intended to endorse any medication and should not replace the expertise and judgment of healthcare professionals.