What is the recommended management for an adult traveler who develops acute diarrhoea (three or more loose stools in 24 hours) while abroad, including rehydration, symptomatic therapy, and antimicrobial options?

Management of Traveller's Diarrhoea

For an adult traveller with acute diarrhoea abroad, start with loperamide 4 mg immediately followed by 2 mg after each loose stool (maximum 16 mg/day), maintain fluid intake with glucose-containing drinks or electrolyte-rich soups, and reserve empirical antibiotics (azithromycin or fluoroquinolones) only for moderate-to-severe cases with fever ≥38.5°C and/or bloody stools. 1, 2

Initial Assessment and Risk Stratification

Determine whether the diarrhoea is uncomplicated or requires immediate medical attention by checking for warning signs:

• High fever (>38.5°C) 1
• Frank blood in stools (dysentery) 1
• Severe vomiting that prevents oral intake 1
• Obvious dehydration (altered mental status, absent pulse, hypotension) 1, 2
• Abdominal distension suggesting ileus 1

If any warning signs are present, seek immediate medical care rather than self-treating. 1

Rehydration: The Foundation of Treatment

For Otherwise Healthy Adults

Maintain adequate fluid intake guided by thirst using glucose-containing drinks (lemonades, sweet sodas, fruit juices) or electrolyte-rich soups. 1, 2

Formal oral rehydration solutions (ORS) are not necessary for otherwise healthy adults who can drink adequately, as they do not shorten illness duration or reduce stool output—they only prevent dehydration. 1, 2 This contrasts with paediatric diarrhoea where ORS is essential.

For Severe Dehydration

If severe dehydration, shock, or altered mental status develops, isotonic intravenous fluids (lactated Ringer's or normal saline) must be administered immediately. 1, 2

Symptomatic Treatment with Loperamide

Loperamide 2 mg is the drug of choice for uncomplicated traveller's diarrhoea. 1, 2

Dosing Regimen

• Initial dose: 4 mg (two 2-mg capsules) immediately 2
• Maintenance: 2 mg after each loose stool 1, 2
• Maximum: 16 mg (eight 2-mg capsules) per 24 hours 2

When to Avoid Loperamide

Do not use loperamide if:

• Bloody stools are present 2, 3
• Fever >38.5°C 1, 2
• Severe dehydration or altered mental status 2
• Abdominal distension suggesting ileus 2

The outdated belief that loperamide "traps toxins" and prolongs illness is not evidence-based; modern evidence shows it safely relieves symptoms and may shorten illness duration in uncomplicated cases. 1, 2

Dietary Management

Continue eating solid food guided by appetite—there is no evidence that fasting benefits adults or that solid food hastens or retards recovery. 1

Recommend small, light meals while avoiding:

• Fatty, heavy, or spicy foods 1, 2
• Caffeine (including cola drinks) 1
• Lactose-containing foods (milk) in prolonged episodes 1, 2

Empirical Antibiotic Therapy

When Antibiotics Are Indicated

Reserve empirical antibiotics for moderate-to-severe traveller's diarrhoea, defined as:

• Incapacitating symptoms preventing planned activities 3
• Fever ≥38.5°C and/or bloody stools (dysentery syndrome) 1, 3
• Three or more loose stools in 8 hours with associated symptoms 4

Do not use antibiotics routinely for mild watery diarrhoea without fever or blood, as most cases are self-limited. 1, 3

First-Line Antibiotic Choice

Azithromycin is now the preferred first-line antibiotic due to widespread fluoroquinolone resistance, particularly for Campylobacter. 3, 4

Dosing options:

• 500 mg single dose or 3
• 500 mg daily for 3 days 3, 4
• 1000 mg single dose for dysentery/febrile diarrhoea 3

Alternative: Fluoroquinolones

Fluoroquinolones (ciprofloxacin, levofloxacin) remain an option but are increasingly compromised by resistance, especially in Asia. 1, 3 They should not be used empirically in regions with high Campylobacter resistance. 3

Combination Therapy

Loperamide can be safely combined with antibiotics in adults with non-dysenteric diarrhoea to hasten symptom relief. 1, 4 This combination is particularly effective for moderate-to-severe traveller's diarrhoea. 1

Critical Contraindication: STEC Infections

Never give antibiotics if Shiga toxin-producing E. coli (STEC) is suspected, as this dramatically increases the risk of hemolytic uremic syndrome (HUS). 1, 3 However, STEC typically presents with bloody diarrhoea after travel to developed countries (not typical traveller's diarrhoea destinations), so this is rarely a concern in the travel medicine context. 1

When to Seek Medical Attention

Seek medical care if:

• No improvement within 48 hours of starting treatment 1, 2
• Symptoms worsen or overall condition deteriorates 1, 2
• Warning signs develop: severe vomiting, dehydration, persistent fever, abdominal distension, or frank blood in stools 1, 2

Practical Travel Kit Recommendations

Travellers to high-risk destinations should carry:

• Loperamide 2 mg capsules 1
• Azithromycin 500 mg tablets (3-day supply) or fluoroquinolone alternative 1, 3
• Oral rehydration salts (optional for otherwise healthy adults) 1

Pre-travel medical advice is strongly encouraged, especially for those travelling to remote areas where medical care may be inaccessible. 1

Common Pitfalls to Avoid

• Do not withhold loperamide based on the outdated belief it prolongs illness—evidence shows it safely shortens symptom duration in uncomplicated cases 1, 2
• Do not use antibiotics routinely for mild watery diarrhoea without fever or blood 1, 3
• Do not use loperamide with bloody diarrhoea or high fever—this can worsen outcomes and increase toxic megacolon risk 2, 3
• Do not assume fluoroquinolones are universally effective—resistance is widespread, particularly in Asia 3, 4