There are several medications to try. Complete report here:
"Treatments reported to be successful for dientamoebiasis include carbarsone, diphetarsone, tetracyclines, paromomycin, erythromycin, hydroxyquinolines and the 5-nitroimidazoles, including metronidazole, secnidazole, tinidazole and ornidazole. It is of note that most current treatment data is based only on small number of case reports...."
The rest of this report:
http://www.sciencedirect.com/science/article/pii/S2211320712000255

A lot of experience with references here:
//www.curezone.org/forums/am.asp?i=474523

CDC Says:
http://www.cdc.gov/parasites/dientamoeba/health_professionals/

Hope this helps,
Grizz