I don't think vidagliptin and sitagliptin are exactly the same but won't argue about it. However Sitagliptin does NOT lead o weight gain . That is why it is becoming increasingly popular with Gp's and patients. This is a fairly new class of drugs . Don't have ime now to look up vildagliptin but will do that later. I just did not want anyone offfered sitagliptin to refuse it because of a misapprehension. Maybe vildagliptin acts slightly differently?