Diarrhea During Leukemia Treatment: How Common It Is and How To Manage It

Diarrhea can be a common side effect during cancer therapy, including treatments used for leukemia, and it may also occur due to infections or the cancer itself. ^[1] Diarrhea that is severe or persistent can lead to dehydration and fatigue, so knowing when to self-manage and when to contact your care team is important. ^[2]

Why Diarrhea Happens in Leukemia Care

• Chemotherapy and targeted drugs: Many cancer medicines irritate the gut lining or change how the intestines absorb fluids, leading to frequent loose stools. ^[1] Some agents (for example, certain tyrosine kinase inhibitors like bosutinib used in chronic myeloid leukemia) commonly cause diarrhea as a treatment side effect, and teams often manage this with dose adjustments and supportive care. [PM10]
• Stem cell transplant: After high‑intensity chemotherapy or stem cell transplantation, diarrhea is common and can result from treatment, infections, medications, or stress. ^[3]
• Infections and antibiotics: Immunosuppression increases the risk of infections such as Clostridioides difficile, which can cause significant diarrhea; diagnosis may be challenging because transplant and leukemia patients often have non‑infectious diarrhea too. [PM7] Antibiotics themselves can also trigger diarrhea. ^[4]
• Cancer-related causes: Some hematologic cancers (including lymphoma) can be associated with diarrhea independent of treatment. ^[4]

When To Call Your Care Team

• Volume and duration: Six or more loose stools per day for more than two days, or diarrhea lasting over 24–48 hours despite self‑care, should prompt a call. ^{[2] [3]}
• Alarm signs: Blood in stool, new or worsening abdominal pain, fever, signs of dehydration (dizziness, dry mouth, reduced urination), or rapid weight loss need urgent attention. ^{[2] [5]}
• After transplant: Any diarrhea lasting more than 24 hours should be reported to the transplant team given risks of dehydration and infection. ^[3]

First-Line Self‑Care Steps

• Hydration: Replace fluids and electrolytes frequently to prevent dehydration; clear liquids and oral rehydration solutions are helpful. ^[6] Dehydration can cause weakness and fatigue, so staying ahead of fluid loss matters. ^[2]
• Gentle diet: Temporarily choose low‑fiber, bland foods (e.g., bananas, rice, applesauce, toast) and small, frequent meals; avoid spicy, greasy foods and caffeine until stools improve. ^{[7] [6]}
• Rest the gut during flares: During intense bouts, some people do better with clear liquids and then gradual reintroduction of solids as symptoms settle. ^[6]

Medications That Can Help

• Loperamide: Generally considered the first‑line anti‑diarrheal for chemotherapy‑induced diarrhea; studies in leukemia and bone marrow transplant populations show high response rates at scheduled doses (e.g., 4 mg every 6 hours) compared with low‑dose octreotide. [PM18] Practical guidance recommends appropriate loperamide use early, with reassessment and fluid support. [PM21]
• Octreotide: If diarrhea does not respond to loperamide, octreotide can be effective; higher doses may be required in some cases. [PM18] This is often used when symptoms are severe or refractory. [PM21]
• Infection‑directed therapy: If C. difficile or another infection is suspected, prompt testing and targeted antibiotics are needed because immunocompromised individuals are at higher risk of complications. [PM7]
• Probiotics (select cases): Some randomized trials suggest probiotics may reduce chemotherapy‑associated gastrointestinal symptoms in leukemia, including diarrhea; however, given variability and infection risks in immunocompromised people, decisions should be individualized by your oncology team. [PM8] Routine prophylactic yeast probiotics are not recommended in transplant settings due to limited benefit and risk of fungemia. ^{[8] [9]}

Practical Management Plan You Can Use

• Track symptoms: Count daily stools, note consistency, cramps, fever, and hydration status so your team can tailor care. [PM21]
• Start loperamide early: If loose stools begin, consider scheduled loperamide per your team’s instructions; many protocols use fixed dosing with reassessment at 24–48 hours. [PM18] [PM21]
• Hydrate and adjust diet: Use oral rehydration solutions and bland foods, avoiding triggers like spicy or fatty meals and alcohol until symptoms settle. ^{[7] [6]}
• Know the red flags: Seek care if diarrhea is frequent or prolonged, if you see blood, develop fever or abdominal pain, or feel dizzy/weak from dehydration. ^[2]
• Post‑transplant vigilance: Contact your transplant team if diarrhea lasts more than 24 hours, as medications can be prescribed and complications prevented. ^[3]

Special Situations To Consider

• Tyrosine kinase inhibitors (e.g., bosutinib): Diarrhea is common and often managed with temporary dose interruption or reduction along with anti‑diarrheals; close communication with your hematology team improves adherence and outcomes. [PM10]
• Irinotecan or sacituzumab regimens: Dedicated algorithms exist for managing treatment‑specific diarrhea, emphasizing early antidiarrheals and escalation strategies. ^{[10] [11] [12]}
• Neutropenic fever: If diarrhea occurs alongside fever in neutropenia, urgent evaluation and empiric antibiotics are required to prevent serious complications. ^{[13] [14]}

Bottom Line

• Diarrhea is relatively common during leukemia treatment and after stem cell transplant, but it can usually be managed effectively with hydration, diet changes, and anti‑diarrheal medications. ^{[1] [3]}
• Call your care team promptly if symptoms are severe, persistent, or accompanied by warning signs, since infections like C. difficile require targeted treatment. ^[2] [PM7]
• For chemotherapy‑induced diarrhea, loperamide is typically first‑line, with octreotide considered if symptoms don’t improve. [PM18] [PM21]