What is the preferred treatment for uncomplicated cases of giardiasis?

The preferred treatment for uncomplicated cases of giardiasis is metronidazole. This medication is an antiprotozoal agent that is particularly effective against Giardia lamblia, the parasite responsible for giardiasis. Metronidazole works by disrupting the DNA of the microorganisms, which inhibits their growth and replication. Typically, a course of metronidazole for giardiasis lasts about five to seven days and is well-tolerated by most patients.

Other medications listed in the choices are not the first-line treatment for giardiasis. Albendazole, while effective against certain parasitic infections like nematodes and some protozoa, is not the standard treatment for giardiasis. Ivermectin is primarily used for infections caused by nematodes and some ectoparasites and does not have efficacy against Giardia. Praziquantel is effective for schistosomiasis and certain cestode infections but is not indicated for giardiasis. This distinction reinforces why metronidazole is chosen as the preferred treatment: it has been extensively studied and proven effective against Giardia, making it the go-to choice in clinical practice for uncomplicated cases of this infection.