What is the recommended treatment for intestinal amoebiasis?

Treatment of Intestinal Amoebiasis

Metronidazole 750 mg orally three times daily for 5-10 days is the recommended first-line treatment for intestinal amoebiasis, and must be followed by a luminal amebicide such as paromomycin to eliminate intestinal cysts and prevent relapse. 1, 2, 3

Diagnostic Confirmation Before Treatment

• Do not treat for amoebiasis unless microscopic examination of fresh feces shows amebic trophozoites, or two different antibiotics given for shigellosis have failed to produce clinical improvement 1, 3
• Use concentrated stool microscopy or fecal PCR to identify Entamoeba histolytica 2
• This diagnostic requirement prevents unnecessary treatment and distinguishes amoebiasis from bacterial dysentery, which is more common 1

Two-Phase Treatment Regimen

Phase 1: Tissue Amebicide (Metronidazole)

Adults:

• Metronidazole 750 mg orally three times daily for 5-10 days 1, 2, 3

Children:

• Metronidazole 30 mg/kg/day for 5-10 days 1, 3

Phase 2: Luminal Amebicide (Essential to Prevent Relapse)

After completing metronidazole, all patients must receive a luminal agent to eliminate intestinal cysts 2, 3, 4

Options include:

• Paromomycin 500 mg orally three times daily for 7 days (adults) 2
• Paromomycin 30 mg/kg/day orally in 3 divided doses for 10 days 3, 4
• Diloxanide furoate 500 mg orally three times daily for 10 days 2, 3, 4

Note: Paromomycin is FDA-approved for intestinal amoebiasis 5

Alternative: Tinidazole

• Tinidazole is FDA-approved for intestinal amoebiasis and may offer superior efficacy with better tolerability 6
• Tinidazole 2 g orally once daily for 3 days showed cure rates of 86-93% in controlled trials 6
• Research studies demonstrate tinidazole superiority over metronidazole (90-96.5% cure rate vs 53.3-58.6%) with fewer side effects 7, 8, 9
• However, tinidazole must also be followed by a luminal amebicide 4

Monitoring Treatment Response

• Clinical improvement should occur within 48 hours of initiating therapy 2
• If no improvement occurs within 2 days, change antibiotics or refer for stool microscopy to confirm diagnosis 1, 3
• At this stage, resistant shigellosis remains more likely than amoebiasis if initial diagnosis was uncertain 1

Critical Pitfall to Avoid

Failure to provide a luminal agent after metronidazole or tinidazole therapy is the most common cause of relapse 2, 4

• Metronidazole and tinidazole are tissue amebicides that treat invasive disease but do not adequately eliminate intestinal cysts 2
• Without luminal treatment, cysts persist in the intestinal lumen and cause recurrent infection 2, 4
• This two-phase approach is essential even when follow-up stool microscopy is negative 4

Special Populations

• Immunocompromised patients receive the same treatment regimen as immunocompetent patients 2
• The single-dose tinidazole regimen is not effective for asymptomatic cyst carriers due to rapid absorption and short duration 10