A method is provided for lowering blood sugar in a subject in need thereof by administering a biguanide anti-hyperglycemic pharmaceutical composition to a subject qualified for over-the-counter access to the biguanide anti-hyperglycemic pharmaceutical composition. In some embodiments, the biguanide anti-hyperglycemic pharmaceutical composition includes N,N-dimethylimidodicarbonimidic diamide, or a pharmaceutically acceptable salt thereof. In some embodiments, the biguanide anti-hyperglycemic pharmaceutical composition includes metformin hydrochloride.