A Cochrane review [Abstract] 1 included 37 studies with a total of 4 487 subjects. 35 of the trials were conducted in 14 different countries highly endemic for amoebiasis, and the remaining two trials were conducted in Sweden. Adults and children with symptoms and positive E. histolytica/E.dispar on stool examination confirmed by E. histolytica antigen detection test or PCR were included. Cases with severe amoebic colitis, complicated disease, or extraintestinal amoebiasis were excluded.
Tinidazole reduced clinical failure (RR 0.28, 95% CI 0.15 to 0.51; 8 studies, n=477) but not parasitological failure (RR 0.64, 95% CI 0.25 to 1.64; 9 studies n=507) compared with metronidazole, which was considered as standard treatment. Tinidazole was associated with fewer adverse events. There was insufficient evidence regarding the efficacy of the other single antiamoebic drugs. Three trials compared various combination regimens with metronidazole alone while four trials compared other combination regimens with alternative single drugs. Combination therapy resulted in fewer parasitological failures when compared with metronidazole alone (RR 0.36, 95% CI 0.15 to 0.86; 720 participants, 3 trials), but it is not known if this led to more adverse effects.
Comment: The quality of evidence is downgraded by study quality (lack of blinding, unclear allocation concealment and sequence generation in most of the studies), by inconsistency (heterogeneity in diagnostic methods, interventions and outcomes), by imprecise or sparse data in some outcomes, and by high probability of reporting or publication bias.
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