What is the best course of treatment for acute diarrhea and vomiting?

Management of Acute Diarrhea and Vomiting

Oral rehydration therapy with reduced osmolarity oral rehydration solution (ORS) is the first-line treatment for acute diarrhea and vomiting, with early resumption of normal diet after rehydration begins. 1

Immediate Rehydration Strategy

Oral rehydration solution is the cornerstone of treatment and should be initiated immediately:

• For adults: Administer 50-100 mL/kg of reduced osmolarity ORS (total osmolarity <250 mmol/L) over 3-4 hours 1
• For children with mild dehydration (3-5% fluid deficit): Give 50 mL/kg of ORS over 2-4 hours 2
• For children with moderate dehydration (6-9% fluid deficit): Give 100 mL/kg of ORS over 2-4 hours 2

When vomiting is present, give small, frequent volumes of 5-10 mL every 1-2 minutes, gradually increasing as tolerated 1. This approach is critical because most patients can successfully rehydrate orally even with ongoing vomiting if given in small, frequent amounts.

• Replace ongoing losses with ORS: 10 mL/kg for each watery stool and 2 mL/kg for each vomiting episode 2
• If oral intake is not tolerated despite small-volume administration, consider nasogastric ORS administration for patients with normal mental status 1

Diet Management During Illness

Resume normal, age-appropriate diet immediately after rehydration begins or during the rehydration process - do not withhold food 1, 3:

• Continue breastfeeding throughout the illness without interruption 1, 2
• For bottle-fed infants, use full-strength lactose-free or lactose-reduced formulas immediately upon rehydration 3
• Older children and adults should resume normal diet guided by appetite, avoiding fatty, heavy, spicy foods and caffeine 3

The evidence strongly supports early refeeding rather than the outdated practice of withholding food, as this improves outcomes and shortens illness duration.

Pharmacological Adjuncts

Antiemetics (Ondansetron)

Ondansetron may be considered for children over 4 years and adults with severe vomiting to facilitate oral rehydration 2, 3:

• Use only after adequate hydration begins - it is not a substitute for fluid therapy 3
• A single oral dose can reduce vomiting episodes and improve ORS tolerance 4
• FDA-approved for prevention of nausea and vomiting, though not specifically labeled for gastroenteritis 5

Antimotility Agents (Loperamide)

Loperamide is CONTRAINDICATED in children under 18 years with acute diarrhea 1, 2, 3:

• May be given to immunocompetent adults with acute watery diarrhea once adequately hydrated 1
• Absolutely avoid in ALL ages with: inflammatory diarrhea, bloody stools, fever, or suspected toxic megacolon 1, 3, 6
• Higher than prescribed doses can cause serious cardiac adverse reactions including QT prolongation 6

Antibiotics

Empiric antibiotics are NOT recommended for most patients with acute watery diarrhea 3:

• Consider antibiotics only for bloody diarrhea, immunocompromised patients, or ill-appearing young infants 3
• For adults with bloody diarrhea: fluoroquinolone or azithromycin based on local susceptibility patterns 3
• For infants <3 months with bloody diarrhea or neurologic involvement: third-generation cephalosporin 3

Warning Signs Requiring Immediate Medical Evaluation

Seek medical attention immediately for 1, 2:

• Inability to tolerate oral fluids despite small-volume administration
• Worsening signs of dehydration (decreased urine output, sunken eyes, lethargy)
• Development of bloody diarrhea
• Significant increase in fever
• Altered mental status or severe lethargy

Common Pitfalls to Avoid

• Do not withhold food - early refeeding improves outcomes 1, 3
• Do not give loperamide to children - this is an absolute contraindication with serious safety concerns 1, 2, 3
• Do not use IV fluids routinely - reserve for severe dehydration, shock, or persistent vomiting despite nasogastric ORS 1
• Do not prescribe antibiotics empirically for watery diarrhea without specific indications 3

Infection Control

Rigorous hand hygiene is essential to prevent transmission 3:

• Wash hands after toilet use, diaper changes, before food preparation and eating
• Use soap and water or alcohol-based sanitizers when caring for patients with diarrhea 3