Synergic effect of albendazole plus metronidazole association in the treatment of metronidazole-resistant giardiasis

Twenty patients with intestinal giardiasis, already resistant to 3-5 previous courses of oral metronidazole, were randomly distributed into 2 different groups: 10 subjects were given oral albendazole (440 mg/two times per day for 7 days) and 10 were submitted to the association of albendazole (400 mg/two times per day for 7 days) plus metronidazole (250 mg/three times per day for 7 days). All patients were evaluated both for clinical and parasitological status, immediately before and after therapy and, then, 4 weeks later. Only 3 patients of those treated with albendazole alone, showed a clinical and parasitological remission at the end of therapy, and one of them relapsed 4 weeks later. All patients who underwent albendazolemetronidazole association responded to the therapy and all except one were defined as "cured" 4 weeks later. Our study demonstrates that albendazole alone is not an effective therapeutic alternative for "metronidazole-resistant" giardiasis. The association of metronidazole plus albendazole seems synergic and deserves further studies.