> If the change doesn't actually result in a therapeutic benefit, then doctors shouldn't prescribe the new drug over the generic. There's also the issue of add

> If the change doesn't actually result in a therapeutic benefit, then doctors shouldn't prescribe the new drug over the generic. There's also the issue of additional state regulation for some drugs. For instance: Adderall. The DEA limits production of amphetamines, and of course Shire (the former patent-holder for Adderall) is going to prefer to produce its patent-protected version over the generic version. For long after there were generic version of Adderall available, Adderall XR ("extended release") was still under patent. Supplies of Adderall were low nationwide, and doctors were pressured to prescribe the XR version to limit abuse potential.