Treatment of Amoebiasis
Metronidazole 750 mg three times daily for 5-10 days is the recommended first-line treatment for amoebiasis in adults, followed by a luminal amebicide to prevent relapse. 1, 2
Initial Treatment Regimen
For adults with intestinal or hepatic amoebiasis:
- Metronidazole 750 mg orally three times daily for 5-10 days 1, 2
- For children: Metronidazole 30 mg/kg/day divided into doses for 5-10 days 1
The FDA approves metronidazole for both acute intestinal amebiasis (amebic dysentery) and amebic liver abscess 2. The same drug regimens used for intestinal amoebiasis are appropriate for amoebic liver abscess 1.
Essential Follow-Up Treatment
After completing metronidazole therapy, all patients must receive a luminal amebicide to eliminate intestinal cysts and prevent relapse. 1 This is a critical step that cannot be skipped, as metronidazole alone has limited efficacy against luminal cysts due to rapid absorption and short duration of action 3.
Luminal amebicide options:
- Paromomycin 30 mg/kg/day orally in 3 divided doses for 10 days 1, 4
- Diloxanide furoate 500 mg orally three times daily for 10 days 1
Paromomycin is FDA-approved specifically for intestinal amebiasis and is effective for both acute and chronic cases 4.
Diagnostic Confirmation
Before initiating treatment, confirm the diagnosis through:
- Microscopic examination of fresh feces showing amebic trophozoites 1
- Consider diagnosis if two different antibiotics for shigellosis have failed 1
- For suspected amoebic liver abscess: perform indirect hemagglutination testing (>90% sensitivity) and ultrasound imaging 1
- If ultrasound is negative but clinical suspicion remains high, obtain CT scan 1
Monitoring Treatment Response
Most patients with amoebic liver abscess respond within 72-96 hours of treatment initiation. 1 If no improvement occurs within 2 days, consider alternative diagnoses or drug resistance 1.
For amoebic liver abscess specifically:
- Surgical or percutaneous drainage is rarely required 1
- Consider drainage only for: diagnostic uncertainty, persistent symptoms after 4 days of treatment, or risk of imminent rupture 1
Common Pitfalls to Avoid
The most critical error is failing to administer a luminal amebicide after metronidazole therapy. Studies show metronidazole alone has a failure rate of 37% for E. histolytica when used without follow-up luminal treatment 3. One long-term study found an 88% cure rate with metronidazole alone, but this still leaves 12% of patients at risk for relapse 5.
Do not use metronidazole or tinidazole alone for asymptomatic carriers - these drugs are ineffective due to rapid absorption and short duration of treatment, with failure rates of 37-62% 3. Asymptomatic carriers require luminal amebicides like paromomycin 4.
Prevention Counseling
Educate patients on: