Treatment of Amoebiasis
For confirmed amoebiasis, treat adults with metronidazole 750 mg three times daily for 5-10 days, followed by a luminal amebicide such as paromomycin to eliminate intestinal cysts and prevent relapse. 1
Diagnostic Confirmation Before Treatment
- Do not initiate treatment for amoebiasis unless microscopic examination of fresh feces demonstrates amebic trophozoites, or two different antibiotics for shigellosis have failed to produce clinical improvement. 2, 1
- For suspected amoebic liver abscess, perform indirect hemagglutination testing (>90% sensitivity) and ultrasound imaging in all cases. 1
- Consider CT scan if ultrasound is negative but clinical suspicion remains high. 1
Primary Treatment Regimen
Metronidazole (Drug of Choice)
- 750 mg orally three times daily for 5-10 days
- 30 mg/kg/day for 5-10 days
Alternative: Tinidazole
- Tinidazole is FDA-approved for intestinal amebiasis and amebic liver abscess in adults and children over 3 years. 4
- Research demonstrates tinidazole provides significantly higher cure rates (96.5%) compared to metronidazole (55.5%) for symptomatic intestinal amebiasis, with better tolerability. 5
- However, metronidazole remains the most widely recommended first-line agent in current guidelines. 2, 1
Intravenous Metronidazole
- For moderate-to-severe amebiasis when oral administration is not feasible, intravenous metronidazole is well-tolerated and highly effective. 6
- Bioavailability is similar between oral and intravenous formulations. 3
Essential Follow-Up Treatment
After completing metronidazole or tinidazole, all patients must receive a luminal amebicide to eliminate intestinal cysts and prevent relapse. 1 This is a critical step often overlooked in clinical practice.
Luminal Amebicide Options:
- Paromomycin: 30 mg/kg/day orally in 3 divided doses for 10 days 1
- Diloxanide furoate: 500 mg orally three times daily for 10 days 1
Treatment Response Monitoring
- Most patients with amoebic liver abscess respond within 72-96 hours of treatment initiation. 1
- If no clinical improvement occurs within 2 days, reconsider the diagnosis or evaluate for drug resistance. 1
- For amoebic liver abscess, surgical or percutaneous drainage is rarely required and should only be considered for: 1
- Diagnostic uncertainty
- Persistent symptoms after 4 days of treatment
- Risk of imminent rupture
Special Clinical Considerations
- In patients with acute severe ulcerative colitis who have recent travel to endemic areas, consider adding metronidazole pending stool microscopy if amoebiasis is suspected. 2
- The same drug regimens used for intestinal amoebiasis apply to amoebic liver abscess. 1
- Metronidazole possesses direct amebacidal activity against Entamoeba histolytica with minimal inhibitory concentrations of 1 mcg/mL or less for most strains. 3
Prevention Counseling
- Emphasize hand washing after bathroom use and before food preparation. 1
- Advise avoiding untreated water and uncooked food in endemic areas. 1
- In men who have sex with men, counsel regarding transmission through oral-anal contact, as this population shows increasing prevalence of invasive amoebiasis. 7