A comparison of the in-vitro activity of some 5-nitroimidazoles and other compounds against Giardia intestinalis.

The activities of 11 5-nitroimidazole compounds have been compared against Giardia intestinalis in vitro using a 3H-thymidine incorporation assay. All the compounds were at least equipotent to, or more active than metronidazole with the exception of panidazole. Satranidazole, ronidazole and S75 0400 A were all about five times more active than metronidazole and warrant further study as potential chemotherapeutic agents for man. No major differences in the response to these compounds was found between two stocks of Giard. intestinalis with the exception of flunidazole. Several other antiprotozoal drugs showed activity against Giard. intestinalis. Berberine sulphate, paromomycin sulphate, erythromycin estolate and sulphasalazine, all of which have been used to treat human patients, showed no activity in vitro.