Treatment of Giardiasis

Giardia lamblia has emerged as the most common intestinal parasite in the United States. This article presents a brief review of the clinically important aspects of giardiasis and evaluates the currently used therapeutic agents. Three drugs have been advocated for the treatment of giardiasis; furazolidone (Furoxone), metronidazole (Flagyl), and quinacrine (Atabrine). None of them, however, is ideal. Metronidazole and quinacrine are more effective than furazolidone, but furazolidone has the advantage of a liquid formulation that makes administration to children easier. Quinacrine is much less expensive than the other two agents but has a somewhat higher rate of side effects and a bitter taste. There is concern about the carcinogenic potential of furazolidone and metronidazole, but this has not been evaluated for quinacrine. In the balance, we conclude that quinacrine is probably the preferable drug to use in the pediatric age group because of proven effectiveness and lower cost.