A method is provided for lowering blood sugar in a subject in need thereof by administering a dipeptidyl peptidase-4 inhibitor pharmaceutical composition to a subject qualified for over-the-counter access to the dipeptidyl peptidase-4 inhibitor pharmaceutical composition. In some embodiments, the dipeptidyl peptidase-4 inhibitor pharmaceutical composition includes saxagliptin, sitagliptin, linagliptin, alogliptin, or a pharmaceutically acceptable salt thereof. In some embodiments, the dipeptidyl peptidase-4 inhibitor pharmaceutical composition includes (1S,3S,5S)-2-[(2S)-2-amino-2-(3-hydroxy-1-adamantyl)acetyl]-2-azabicyclo[3.1.0]hexane-3-carbonitrile or a pharmaceutically acceptable salt thereof.
