Symptom-Based Treatment Guide for Acute Gastroenteritis (AGE) in Adults: Diarrhea, Abdominal Cramping Pain, Nausea & Vomiting (N/V), and Fever Bacterial Diarrhea
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| 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
- Assess hydration → Give ORS for mild to moderate dehydration
- Identify red flags → Bloody stool, high-grade fever, toxic signs
- 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)
🧾 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
🚫 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)
- ORS Powder – 1 sachet per 200 ml, sip frequently
- Dehecta (Diosmectite) – 1 sachet TID between meals
- Domperidone 10 mg – 1 tab TID before meals
- Hyoscine 10 mg – 1 tab TID after meals (prn for cramping)
- Norfloxacin 400 mg – 1 tab BID x 3 days (only if bacterial signs)
🧠 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 |
💬 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
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