Introduction: Giardia intestinalis is the most common intestinal protozoa in developing countries, including Iran. Treatment of infection by metronidazole has some difficulties because of long course of therapy (7-10 days) and various side effects. The objective of this study was to determine the efficacy and side effects of tinidazole compared with metronidazole in the treatment of G. intestinalis infection in children.

  Methods: In a randomized controlled clinical trial , 106 subjects ( 69 males, 37 females) with Giardia intestinalis infection were treated with tinidazole or metronidazole. Tinidazole 50 mg/kg single dose and metronidazole 15 mg/kg three times a day for 7 days were given orally to children. Parasitological cure was documented when there was 3 times negative stool examination for G. intestinalis at 1-2 weeks after therapy.

  Results: Thirty seven of 42 individuals (88.1%) treated with tinidazole and 43 of 64 children (67.2%) treated with metronidazole had parasitological cure. Cure rate between two groups was significantly different (P<0.01). No major side effects were observed except two cases in metronidazole group who had mild headache and abdominal pain for two days and some had metal taste and three cases in tinidazole group had nausea, dizziness and headache.

  Conclusion: We conclude, tinidazole has a higher efficacy than metronidazole in the treatment of G. intestinalis infection and also has a few side effects. Because of single dose administration, short course of therapy and good compliance of patients, this preparation is preferred to metronidazole in the treatment of Giardia intestinalis infection.

  Keywords: Giardiasis, tinidazole, clinical trial

  Hakim 2005 8(1) 16-21.