Treatment of intestinal E. histolytica and G. lamblia with metronidazole, tinidazole and ornidazole: a comparative study.

Metronidazole, tinidazole and ornidazole were compared in patients treated for Entamoeba histolytica or Giardia lamblia intestinal infections. Only patients with three positive stool specimens for trophozoites and/or cysts of E. histolytica or G. lamblia by the merthiolate iodine formaldehyde (MIFC) technique were included. Criteria for cure were at least 10 negative stool specimens over 3 weeks after completing therapy. Fifty-three male patients (aged 9-65 years) had E. histolytica infection. Seventeen received metronidazole (1.5 g daily for 10 days), 18 tinidazole (1.5 g daily for 10 days) and 18 ornidazole (1 g daily for 10 days). Metronidazole yielded 88%, tinidazole 67% and ornidazole 94% cure rates. Side reactions were minor. Eighty patients had G. lamblia infection, of whom 20 received metronidazole (0.5 g daily for 10 days), 30 tinidazole (single 2 g dose) and 30 ornidazole (single 1 g dose). Cure rates were 95% for metronidazole, 90% for tinidazole and 97% for ornidazole with no side reactions.