How Does Tinidazole Compare with Metronidazole?

Summary

Tinidazole was compared with metronidazole in a series of controlled, randomised trials involving 510 patients with symptomatic intestinal amoebiasis, 100 patients with amoebic liver abscess and 186 children with symptomatic giardiasis. A standard protocol was used for all trials in the same indication.

In symptomatic intestinal amoebiasis, the divided dose regimen consisted of 600mg tinidazole twice daily, or 400mg metronidazole thrice daily, for 5 days; the single daily dose regimen consisted of 2g tinidazole or 2g metronidazole given once daily for 3 days. Success was defined as complete or marked relief of symptoms and signs with clearance of Entamoeba histolytica from the stools. In patients who passed trophozoites the differences between the drug regimens were not significant, but the trend in favour of tinidazole was significant (p < 0.01). Among those who passed cysts, tinidazole given once daily was more effective than metronidazole (p < 0.01). Tinidazole given as a single daily dose was also more effective than when given as divided doses (p < 0.05). The incidence of gastrointestinal side-effects was significantly less in patients given tinidazole than in those given metronidazole.

In amoebic liver abscess, both tinidazole and metronidazole were given in a dose of 2g once daily for 2 days. With tinidazole, 96 % of patients had complete recovery, compared to 75.5 % treated with metronidazole. The difference between drugs was significant (p < 0.05). Among those who recovered completely, 79.2% of those on tinidazole showed a rapid improvement within one week as opposed to 48.6 % of those on metronidazole (p < 0.01). Gastrointestinal side-effects occurred in 6 % of patients given tinidazole and 41 % of those given metronidazole (p < 0.01).

In symptomatic giardiasis, the dose of both tinidazole and metronidazole was calculated as 50mg/kg body weight to be given once only. With tinidazole, success was achieved in 88.3 % of patients; with metronidazole, in 46.7% of patients. The difference was significant (p < 0.01). The incidence of reported gastrointestinal side-effects was 8.5 % in the imidazole group and 2.2% in the metronidazole group.

Neither tinidazole nor metronidazole was found to cause any abnormalities in blood count urine analysis or blood chemistry.

The results indicate that tinidazole is more effective and better tolerated than metronidazole when given as a short course in single daily doses for symptomatic intestinal amoebiasis and amoebic liver abscess and as a single dose in symptomatic giardiasis.