What is the recommended dosage and treatment protocol for diloxanide (luminal amoebicide) in a patient with intestinal amoebiasis?

How to Give Diloxanide in Amoebiasis

Diloxanide furoate should be given at 500 mg orally three times daily for 10 days as a luminal amebicide after completing tissue-active therapy with metronidazole or tinidazole, or as monotherapy for asymptomatic intestinal amoebiasis. 1, 2

Treatment Protocol Based on Clinical Presentation

For Asymptomatic Intestinal Amoebiasis (Cyst Passers)

• Diloxanide furoate 500 mg orally three times daily for 10 days as monotherapy 1, 3
• This is the drug of choice for asymptomatic carriage of pathogenic Entamoeba histolytica strains 3
• Diloxanide achieves high luminal concentrations and has greater efficacy than metronidazole for asymptomatic disease, with parasite clearance rates of 81-96% 4

For Symptomatic Intestinal Amoebiasis or Amoebic Liver Abscess

Two-phase treatment approach is mandatory to prevent relapse:

1. Initial tissue-active phase:

   • Metronidazole 750 mg orally three times daily for 5-10 days 1, 5
   • Alternative: Tinidazole 2 grams once daily for 3-5 days 2

2. Follow-up luminal phase (essential):

   • Diloxanide furoate 500 mg orally three times daily for 10 days 1, 2
   • Alternative: Paromomycin 30 mg/kg/day orally in 3 divided doses for 10 days 1

Mechanism and Rationale

Diloxanide works by blocking protein synthesis in E. histolytica trophozoites, preventing their conversion to more virulent cyst forms 4. The ester formulation allows high luminal concentrations, making it particularly effective against intestinal cysts that metronidazole cannot adequately eliminate 4, 3.

Critical pitfall: Failure to provide luminal therapy with diloxanide after metronidazole is the most common cause of treatment relapse 5. Metronidazole alone does not eliminate intestinal cysts, which can lead to recurrent infection 3, 6.

Pediatric Dosing

While the provided evidence focuses primarily on adult dosing, diloxanide can be used in children with appropriate weight-based adjustments 1.

Combination Therapy Option

A fixed-dose combination of diloxanide furoate 500 mg plus metronidazole 400 mg taken three times daily for 5 days has demonstrated 100% parasitic clearance in both amoebiasis and giardiasis 7. However, the standard sequential approach (metronidazole followed by diloxanide) remains the guideline-recommended strategy 1, 5.

Adverse Effects

Diloxanide is very well tolerated 3. Common side effects include flatulence, anorexia, headache, and urticaria, but these are generally mild 4.

Treatment Monitoring

• Clinical improvement should occur within 48 hours of initiating metronidazole therapy 5
• For amoebic liver abscess, most patients respond within 72-96 hours 1, 2
• If no improvement occurs within 2 days, consider alternative diagnoses or drug resistance 1
• Stool examination should be repeated after completing the full course to confirm parasitic clearance 7