I was diagnosed with giardia. what is treatment in us?

There are several: But Metronidazole is often used.

Giardia Lamblia: Tx can include metronidazole, tinidazole & nitazoxanide. Giardiasis is a waterborne illness caused by Giardia parasite. Sx's – there may be no sx's or diarrhea, oily floating stool, gas, nausea, vomiting & abdominal cramps. If untreated it can cause bloody diarrhea, dehydration & weight loss. Diagnosis- via blood test for antibodies & checking stool for parasites.