Desmopressin shifts concentration response curves of GPIIb/IIIa antagonists to the right. GPIIb/IIIa inhibitors were added to whole blood in vitro before and after DDAVP infusion. Eptifibatide (top), tirofiban (middle), and abciximab (bottom) concentration-dependently inhibited platelet function, as measured by the PFA-100. Horizontal dashed lines show the upper limit of normal CT values. The horizontal solid lines show the maximal measurable CT. Data are presented as mean ± SEM. ^*P < .05, ^**P < .01 (before DDAVP vs after DDAVP). DDAVP infusion caused a shift in the concentration response curves of all 3 GP IIb/IIIa inhibitors to the right in lepirudinised blood (n = 10).