Diarrhea Management

General Recommendations

Oral rehydration solutions (ORS) with WHO-recommended electrolyte concentrations should be used for all patients with diarrhea, as oral rehydration is essential for these patients, according to the World Health Organization 1, 2
For mild to moderate dehydration, oral rehydration is sufficient, but for severe dehydration or signs of hypovolemia, an initial fluid bolus of 20 mL/kg should be administered if the patient is tachycardic or potentially septic, and rapid fluid replacement should continue until clinical signs of hypovolemia improve, aiming for adequate central venous pressure and urine output >0.5 mL/kg/h 2

Loperamide is the preferred antidiarrheal agent due to its local action in the intestine and minimal systemic absorption, with an initial dose of 4 mg followed by 2 mg after each unformed stool, up to a maximum of 16 mg daily, as recommended by the American Society of Clinical Oncology 2
For refractory cases, other opioids such as tincture of opium, morphine, or codeine may be used, and octreotide 100-150 μg SC/IV three times daily can be titrated up to 500 μg three times daily, while budesonide 9 mg once daily can be used for chemotherapy-induced diarrhea refractory to loperamide 2, 3
Bile acid sequestrants (cholestyramine, colestipol, colesevelam) can be used for bile salt malabsorption, as recommended by the American Gastroenterological Association 2, 4

Patients should maintain fluid intake with glucose-containing fluids and electrolyte-rich soups, and avoid spices, coffee, and alcohol, as well as reduce insoluble fiber intake and consider avoiding milk and dairy products (except yogurt and firm cheeses), according to the European Society for Clinical Nutrition and Metabolism 2, 5
Early resumption of feeding may speed recovery rather than fasting, and dietary modifications, such as a bland diet (BRAT: bananas, rice, applesauce, and toast), avoiding lactose (except for yogurt and hard cheese), and reducing insoluble fiber intake, can help manage diarrhea 2, 5

Hospitalization is indicated for patients with diminished performance status, signs of alarm (such as fever, severe dehydration, neutropenia, or blood in stool), or severe illness, and antibiotics are not routinely recommended for most cases of acute diarrhea, but should be considered for immunocompromised patients with severe illness and bloody diarrhea, or patients with fever, abdominal pain, and bloody diarrhea, as recommended by the Infectious Diseases Society of America 2, 6
If bacterial infection is confirmed, quinolones are currently the empirical antimicrobials of choice, according to the American College of Gastroenterology 5

The severity of diarrhea can be classified into four grades:

Grade	Description
1	Increase of <4 stools/day above baseline
2	Increase of 4-6 stools/day
3	Increase of ≥7 stools/day, incontinence, or hospitalization
4	Potentially life-threatening consequences

Treatment guidelines for each grade are as follows:
If clinical improvement is not observed within 48 hours, loperamide should be discontinued and the patient reassessed, and non-infectious conditions should be considered if symptoms persist beyond 14 days, with reevaluation of fluid and electrolyte balance and nutritional status in patients with persistent symptoms, as recommended by the American Gastroenterological Association 6
Consider reducing the dose or suspending chemotherapy if diarrhea persists, and for diarrhea induced by 5-FU or capecitabine, consider using uridine triacetate 3, 2