Symptom-Based Treatment Guide for Acute Gastroenteritis (AGE) in Adults: Diarrhea, Abdominal Cramping Pain, Nausea & Vomiting (N/V), and Fever Bacterial Diarrhea

Symptom	First-Line Drug	Dose & Frequency (Adult)	Alternative (less preferred)	Dose & Frequency (Adult)	Notes
Diarrhea	Diosmectite	1 sachet (3g) PO TID between meals	Loperamide	2 mg PO Q6H PRN (Max 16 mg/day)	Use Loperamide only if afebrile and non-bloody
Cramping Pain	Hyoscine (Amcopan)	10 mg PO TID after meals	—	—	Antispasmodic relief for colic pain
N/V	Domperidone	10 mg PO TID before meals	Metoclopramide	10 mg PO/IV Q6–8H (Max 30 mg/day)	Domperidone safer, fewer CNS/EPS effects
Bacterial Diarrhea	Norfloxacin	400 mg PO BID 1 hour before meals	—	—	Empirical use only when invasive bacteria suspected

🦠 Management of Acute Gastroenteritis (AGE) and Food Poisoning

Symptoms: Diarrhea ± Nausea/Vomiting ± FeverSetting: Primary Care / OPD / ER (non-toxic patients)

🔑 Clinical Principles

1. Assess hydration → Give ORS for mild to moderate dehydration

2. Identify red flags → Bloody stool, high-grade fever, toxic signs

3. Determine likely etiology

   • Viral: Most common in children, self-limiting

   • Bacterial: More common in food poisoning (undercooked meat, seafood, contaminated water)

   • Toxin-mediated: Abrupt onset of vomiting, short-lived (e.g., Staph aureus, Bacillus cereus)

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🧾 Symptom-Specific Management

🟢 1. Diarrhea

✅ Preferred: Diosmectite (Dehecta)

• Natural clay adsorbent

• Binds bacterial toxins, viruses, and inflammatory mediators

• Shortens diarrhea without affecting motility

• Safe for all ages, no systemic absorption

• Especially good for children and viral diarrhea

⚠️ Use with Caution: Loperamide (Impelium)

• µ-opioid agonist → reduces GI motility

• Prefer only if diarrhea is non-bloody and afebrile

• Avoid in suspected invasive diarrhea (bloody stool, high fever)

• Not suitable for children < 2 years
  

🟢 2. Abdominal Cramp / Colic

✅ Preferred: Hyoscine Butylbromide (Amcopan, Buscopan)

• Anticholinergic spasmolytic

• Relieves colicky abdominal pain

• Minimal systemic absorption

• Safe short-term relief in viral and toxin-mediated diarrhea

⚠️ Avoid in:

• Elderly with BPH or glaucoma

• Constipation-dominant patients
  

🟢 3. Nausea and Vomiting (N/V)

✅ Preferred: Domperidone (Motidom-M)

• Peripheral D2 antagonist

• Increases gastric motility

• Minimal extrapyramidal side effects due to poor CNS penetration

• Well-tolerated even in children

⚠️ Use with Caution: Metoclopramide (Maxolon)

• Central + peripheral D2 antagonist

• EPS risk (esp. in adolescents, young women)

• Preferred only in migraine-associated nausea or severe vomiting in adults
  

🟢 4. Antibiotic (Only if Indicated)

✅ Preferred in Bacterial Food Poisoning: Norfloxacin 400 mg BID x 3–5 days

• Fluoroquinolone with gram-negative coverage

• Indicated in:

  • Profuse watery diarrhea with signs of systemic illness

  • Traveler’s diarrhea

  • Suspected bacterial gastroenteritis with high fever

⚠️ Not Preferred for Viral Gastroenteritis

• Antibiotics are not helpful in most viral AGE cases

• Overuse leads to resistance and gut flora disruption
  

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🚫 When to Avoid Medications:

Medication	Avoid When...
Loperamide	Bloody stool, high fever, C. difficile suspected
Norfloxacin	Viral diarrhea, children < 12 years, pregnancy
Metoclopramide	History of dystonia, Parkinson’s disease
Hyoscine	Suspected obstruction, elderly with glaucoma
Domperidone	Known QT prolongation, with macrolides/azole

📝 Example Thai OPD Prescription (Non-bloody AGE)

1. ORS Powder – 1 sachet per 200 ml, sip frequently

2. Dehecta (Diosmectite) – 1 sachet TID between meals

3. Domperidone 10 mg – 1 tab TID before meals

4. Hyoscine 10 mg – 1 tab TID after meals (prn for cramping)

5. Norfloxacin 400 mg – 1 tab BID x 3 days (only if bacterial signs)
   

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🧠 Take-Home Summary Table

Symptom	First-Line Drug	Alternative (less preferred)	Notes
Diarrhea	Diosmectite	Loperamide	Use Loperamide only if afebrile & non-bloody
Cramping Pain	Hyoscine	—	Antispasmodic relief
Nausea/Vomiting	Domperidone	Metoclopramide	Domperidone safer, fewer CNS effects
Bacterial Diarrhea	Norfloxacin	—	Empirical use only when indicated

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💬 Patient Advice

• Maintain hydration with ORS, especially with fever or frequent diarrhea

• Watch for red flags: persistent fever, bloody stools, decreased urine, altered mental status

• Avoid raw/undercooked meat, unpasteurized milk, street food in poor hygiene areas

Would you like me to create an OSCE summary table or SOAP note format from this article?