What medication is recommended for treating diarrhea?

Medication for Diarrhea

Oral rehydration solution (ORS) is the first-line medication for treating diarrhea of any cause, followed by loperamide for symptomatic relief in appropriate patients. 1

Primary Treatment: Rehydration

Reduced osmolarity oral rehydration solution (ORS) is strongly recommended as first-line therapy for mild to moderate dehydration in all age groups with acute diarrhea. 1 This is not merely supportive care—it is the definitive medication that addresses the primary pathophysiology and reduces mortality. 1

When to Use IV Fluids Instead

• Administer isotonic intravenous fluids (lactated Ringer's or normal saline) when there is severe dehydration, shock, altered mental status, or failure of ORS therapy. 1
• In severe dehydration, continue IV rehydration until pulse, perfusion, and mental status normalize, then transition to ORS for remaining deficit replacement. 1

Symptomatic Medication: Loperamide

Adults

Loperamide is the drug of choice for symptomatic relief in immunocompetent adults with acute watery diarrhea. 1

• Initial dose: 4 mg followed by 2 mg after each unformed stool or every 2-4 hours 1, 2
• Maximum daily dose: 16 mg 1, 2
• Clinical improvement is usually observed within 48 hours 2

Critical Contraindications for Loperamide

Do NOT give loperamide in the following situations:

• Children <18 years of age with acute diarrhea 1
• Any patient with suspected inflammatory diarrhea, bloody diarrhea, or fever (risk of toxic megacolon) 1, 2
• Patients with abdominal distention or ileus 2
• Patients taking drugs that prolong QT interval (risk of cardiac arrhythmias including Torsades de Pointes) 2

Pediatric Patients (2-12 years)

For children 2-12 years, use liquid formulation (1 mg/5 mL) rather than capsules for ages 2-5 years. 2 However, antimotility drugs should generally not be given to children <18 years with acute diarrhea per IDSA guidelines. 1

Alternative Symptomatic Medications

Second-Line Agents

If loperamide fails after 48 hours at high doses, discontinue it and initiate octreotide (starting dose 100-150 mcg subcutaneously/IV three times daily, can titrate up to 500 mcg three times daily). 1

Other opioids (tincture of opium, morphine, codeine) can be used as alternatives to loperamide. 1

Antiemetics

Ondansetron may be given to children >4 years and adolescents with acute gastroenteritis and vomiting to facilitate oral rehydration tolerance. 1

Adjunctive Therapies

Probiotics

Probiotic preparations may be offered to reduce symptom severity and duration in immunocompetent adults and children with infectious or antibiotic-associated diarrhea. 1 However, probiotics are not recommended for early treatment in otherwise healthy adults with acute diarrhea. 1

Zinc Supplementation

Oral zinc supplementation reduces diarrhea duration in children 6 months to 5 years in countries with high zinc deficiency prevalence or signs of malnutrition. 1

Specialized Situations

For bile salt malabsorption, bile acid sequestrants (cholestyramine, colestipol, colesevelam) may be active adjuvant therapy. 1

For chemotherapy-induced diarrhea refractory to loperamide, oral budesonide may be considered. 1

When Antimicrobials Are NOT Indicated

In most patients with acute watery diarrhea without recent international travel, empiric antimicrobial therapy is NOT recommended. 1 Exceptions include immunocompromised patients or ill-appearing young infants. 1

Antimicrobials should be avoided in STEC O157 and other Shiga toxin-producing E. coli infections (risk of hemolytic uremic syndrome). 1

Dietary Management

Resume age-appropriate usual diet during or immediately after rehydration is completed. 1

Maintain adequate fluid intake guided by thirst, using glucose-containing drinks or electrolyte-rich soups. 1

Avoid fatty, heavy, spicy foods, caffeine, and alcohol. 1

Consider avoiding lactose-containing foods (except yogurt and firm cheeses) in prolonged episodes. 1

When to Seek Medical Attention

Patients should seek medical evaluation if:

• No improvement within 48 hours 1
• Symptoms worsen or overall condition deteriorates 1
• Warning signs develop: severe vomiting, obvious dehydration, persistent fever >38.5°C, frank blood in stools, or abdominal distention 1

Common Pitfalls to Avoid

Do not use antimotility agents as a substitute for fluid and electrolyte therapy—they are ancillary only after adequate hydration. 1

Do not withhold ORS in patients who are vomiting—contrary to common practice, ORS should still be offered as patients can often tolerate small frequent sips. 1

Do not exceed recommended loperamide doses—higher doses significantly increase risk of cardiac arrhythmias and sudden death. 2

Do not use loperamide in elderly patients taking QT-prolonging medications (Class IA or III antiarrhythmics, certain antipsychotics, antibiotics like moxifloxacin). 2