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  Giardia trophozoites under a scanning electron microscope.

Giardia trophozoites under scanning electron microscope. Credit: Waterborne Disease Prevention Branch, CDC

Several drugs can be used to treat Giardia infection. Effective treatments include metronidazole, tinidazole, and nitazoxanide 1. Alternatives to these medications include paromomycin, quinacrine, and furazolidone 1,2. Some of these drugs may not be routinely available in the United States.

Different factors may shape how effective a drug regimen will be, including medical history, nutritional status, and condition of the immune system 3-5. Therefore, it is important to discuss treatment options with a healthcare provider.

  1. Drugs for Parasitic Infections: The Medical Letter; 2010.
  2. Escobedo AA, Cimerman S. Giardiasis: a pharmacotherapy review. Expert Opin Pharmacother. 2007;8(12):1885-1902.
  3. Upcroft JA, Upcroft P. Drug resistance and Giardia. Parasitol Today. 1993;9(5):187-90.
  4. Muller J, Ley S, Felger I, Hemphill A, Muller N. Identification of differentially expressed genes in a Giardia lamblia WB C6 clone resistant to nitazoxanide and metronidazole. J Antimicrob Chemother. 2008;62(1):72-82.
  5. Solaymani-Mohammadi S, Genkinger JM, Loffredo CA, Singer SM. A meta-analysis of the effectiveness of albendazole compared with metronidazole as treatments for infections with Giardia duodenalis. PLoS Negl Trop Dis. 2010;4(5):e682.