Millions are being spent to protect profits patents:

Generic drugs are the centerpiece of efforts to tame growth in America’s prescription-drug bill, which topped $270 billion in 2006. When a doctor writes a prescription for a brand-name drug, pharmacists are usually permitted in most states to make an automatic switch to a generic judged equivalent by the FDA.

The epilepsy legislation would carve out an exception to that rule, with many of the bills requiring that doctors explicitly approve such a switch. Tennessee has passed a weaker version that requires doctor notification but not consent. Around 25 other states have considered some form of restriction in the past year.