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Treatment diarrhoea can turn dangerous quickly, especially with a low blood count. Drink plenty and start loperamide at the first loose stool if your team has told you to. Call the 24-hour line at once if it does not settle within a day, if there are seven or more stools a day, or with fever, blood, vomiting or dizziness. If cancer tablets are the cause and loperamide fails, stop them and ring.
The usual approach, as written by eviQ (Cancer Institute NSW) and NCI PDQ, follows the 2004 expert panel (Benson et al.): grade the diarrhoea with CTCAE, look for complicating features, and split uncomplicated from complicated diarrhoea. Uncomplicated grade 1 or 2 diarrhoea is managed at home with clear fluids, dietary changes and standard-dose loperamide (4 mg, then 2 mg every 4 hours or after each loose stool until 12 hours free of diarrhoea), increased to 2 mg every 2 hours if it persists beyond 24 hours. Grade 3 or 4 diarrhoea, or grade 1 or 2 with cramping, fever, sepsis, neutropenia, bleeding, nausea or vomiting, dehydration or falling performance status, or diarrhoea lasting beyond 48 hours on loperamide, is complicated: it usually needs admission, stool cultures, intravenous fluids, antibiotics and subcutaneous octreotide (100 to 150 micrograms three times daily, escalated to 500 micrograms). MASCC/ISOO recommend octreotide of at least 100 micrograms twice daily when loperamide fails after chemotherapy associated with transplant (level II), and suggest Lactobacillus probiotics to prevent diarrhoea from pelvic radiotherapy (level III). Anticancer treatment is interrupted and the dose modified by the regimen's own rules. Irinotecan, sacituzumab govitecan and neratinib have their own protocols; checkpoint inhibitor diarrhoea is immune colitis and is excluded. The latest ESMO guideline (2018) could not be read.
Why: Diarrhoea from treatment can become dangerous within a day or two; people who know what to do and when to ring act sooner.
“Educate patient about: the likelihood of experiencing diarrhoea prior to commencement of treatment”
Why: The grade and any warning signs decide whether it can be managed at home or needs hospital care.
“The severity of treatment induced diarrhoea should be evaluated as per the CTCAE grading table below.”
Why: Diarrhoea from immunotherapy can be inflammation of the bowel that needs steroids; slowing the bowel can hide it.
“If immune colitis is suspected antidiarrhoeal agents are contraindicated and management of this and any diarrhoea as a result of these agents should be according to the Management of immune related adverse events (irAEs) document.”
Why: Diarrhoea with these features can lead to dehydration, kidney damage and infection, and needs drips, tests and closer watching.
“Uncomplicated patients presenting with grade 1-2 diarrhoea may be managed conservatively in the outpatient setting. However, patients with grade 3-4 diarrhoea or grade 1-2 diarrhoea plus one or more additional symptoms of cramping, fever, sepsis, neutropenia, frank bleeding, nausea or vomiting, dehydration or declining performance status, will often require hospital admission.”
Why: Replacing lost fluid prevents dehydration, and a stool record shows the team whether things are improving.
“oral rehydration, approximately 8 to 10 large glasses of clear liquids per day (e.g. water, sports drinks, clear juices or broth)”
Why: Loperamide slows the bowel and controls most treatment-related diarrhoea when it is started early.
“4 mg at the first onset of diarrhoea followed by 2 mg every 4 hours or after every unformed stool and continued until diarrhoea free for 12 hrs.”
Why: Diarrhoea that does not respond to standard loperamide is more likely to become severe and needs a different approach.
“If diarrhoea persists beyond 24 hours, the dose of loperamide should be increased to 2 mg every 2 hours. If diarrhoea persists beyond 48 hours, the patient’s symptoms should be considered complicated and managed as grade 3-4 diarrhoea.”
Why: Infection and dehydration must be found and treated quickly, particularly when the blood count is low.
“Treatment may include aggressive intravenous rehydration, antidiarrhoeal medications, antibiotics, octreotide (for chemotherapy and targeted therapy induced diarrhoea, unresponsive to high dose loperamide) and a diagnostic work up. Stool should be sent for culture in these patients and electrolytes closely monitored.”
Why: Octreotide reduces the fluid the bowel pours out and controls most diarrhoea that loperamide does not.
“The recommended starting dose is 100 to 150 micrograms three times daily given subcutaneously (alternatively can give 25-50 micrograms/hour via intravenous infusion), with the dose rapidly escalated to 500 micrograms three times a day subcutaneously/intravenously.”
eviQ, Cancer Institute NSW 2022 · MASCC/ISOO level II (transplant-associated chemotherapy)
Why: Continuing the drug that causes the diarrhoea makes it worse; a lower dose can allow treatment to continue safely.
“Treatment with anti-cancer agents may need to be interrupted until symptoms have resolved and dose modification may be considered.”
Why: With tablets at home, nobody else will stop the drug; carrying on can turn mild diarrhoea into a dangerous one.
“Patients taking oral anti-cancer therapy must be informed that if they develop diarrhoea which does not settle with loperamide, then they must STOP taking oral anti-cancer therapy and contact their treating team.”
Why: Some long-lasting diarrhoea after pelvic radiotherapy, bowel or pancreatic surgery or some drugs is caused by bile acids and has its own treatment.
“For patients who have chronic loose stools that persist throughout treatment, bile acid malabsorption may be the cause”
How care is usually carried out, read from the guidelines and standards cited. Your own team's protocol and their judgement come first; this page is for understanding it, not for doing it yourself.
No current guideline could be read in full that is newer than the 2004 expert panel on which the common approach rests: the 2018 ESMO guideline refused a script. The best-supported practice in the sources read is the eviQ version of that approach (also described by NCI PDQ, 2025): CTCAE grading with a check for complicating features, home management of uncomplicated grade 1 or 2 diarrhoea with fluids and standard-dose loperamide, escalation to high-dose loperamide at 24 hours, and admission with stool tests, intravenous fluids, antibiotics and octreotide for complicated diarrhoea. MASCC/ISOO give the only graded recommendation read, for octreotide after loperamide fails in transplant-associated chemotherapy (level II, 2014, unchanged in 2020). The sources differ on octreotide: eviQ reserves it for loperamide failure, while the 2004 panel, as PDQ reports it, would use high-dose octreotide first for grade 3 or 4 diarrhoea.
eviQ, Cancer Institute NSW 2022 · National Cancer Institute 2025 · MASCC/ISOO, Cancer 2014 · MASCC/ISOO, Cancer 2020 · Journal of Clinical Oncology 2004 · ESMO, Annals of Oncology 2018
Where it differs: Uses loperamide 2 mg every 2 hours from the first day of low-grade diarrhoea, followed by octreotide 100 to 150 micrograms every 8 hours, and octreotide 500 to 1500 micrograms every 8 hours as first-line treatment for grade 3 or 4 diarrhoea; suggests severe radiotherapy diarrhoea may be cared for in an outpatient unit or with intensive home nursing rather than in hospital.
Evidence: Expert panel consensus. PDQ notes that the optimal octreotide dose has not been established and that, in a prospective study of 32 people with diarrhoea refractory to loperamide, octreotide 100 micrograms three times a day resolved it in 30.
National Cancer Institute 2025 · Journal of Clinical Oncology 2004
Where it differs: Adds a probiotic containing Lactobacillus during pelvic radiotherapy or chemoradiotherapy to prevent diarrhoea.
Evidence: MASCC/ISOO suggestion at level III (2020, maintained from 2014). eviQ limits it to pelvic cancers and advises avoiding it in people who are or may become neutropenic, because of the risk of infection.
Where it differs: Two tablets three or four times a day until 12 hours free of diarrhoea, instead of loperamide.
Evidence: eviQ lists it as an alternative but says loperamide appears more effective and is the agent guidelines recommend.
| Recommendation | Grade, as printed | Source |
|---|---|---|
| Octreotide of at least 100 micrograms subcutaneously twice daily for diarrhoea after standard- or high-dose chemotherapy associated with transplant, when loperamide is ineffective “The panel recommends that octreotide, at a dose of ≥100 μg subcutaneously twice daily, be used to treat diarrhea induced by standard‐ or high‐dose chemotherapy associated with HSCT, if loperamide is ineffective (II).” | Recommendation, level of evidence II | MASCC/ISOO, Cancer 2014 |
| Lactobacillus probiotics may help prevent diarrhoea from pelvic radiotherapy or chemoradiotherapy “The panel suggests that probiotics containing Lactobacillus spp. may be beneficial for the prevention of RT‐induced or RT‐CT–induced diarrhea in patients with pelvic malignancy.” | Suggestion, level of evidence III | MASCC/ISOO, Cancer 2020 |
| Loperamide may be less effective in grade 3 or 4 diarrhoea “Regardless of the dose, however, loperamide may be less effective in patients with grade 3 or 4 diarrhea.” | PDQ level of evidence I | National Cancer Institute 2025 |
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Shares European Society for Medical Oncology (ESMO) and the tags protocol, supportive-care.
Shares Multinational Association of Supportive Care in Cancer, European Society for Medical Oncology (ESMO) and the tags protocol, supportive-care.
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