In one embodiment a layered pharmaceutical formulation includes two or more pharmaceutical layers and an intermediate layer disposed between at least two of the two or more pharmaceutical layers, the intermediate layer configured to dissolve in vivo to thereby leave the two or more pharmaceutical layers substantially intact. In one embodiment, an active pharmaceutical ingredient in at least one of the pharmaceutical layers is selected from bupropion, zonisamide, naltrexone, topiramate, phentermine, metformin, olanzapine and fluoxetine.