The effects of state‐level pharmacist regulations on generic substitution of prescription drugs
研究美国两种州级法律（强制替代法和推定同意法）对药剂师用非专利药替代品牌药的影响，发现推定同意法使消费者购买品牌药的概率降低3.2个百分点，而强制替代法效果不显著，差异源于药剂师的利润动机。
Substituting generic for brand name drugs whenever possible has been proposed to control prescription drug expenditure growth in the United States. This work investigates two types of state laws that regulate the procedures under which pharmacists substitute bioequivalent generic versions of brand name drugs. Mandatory substitution laws require pharmacists to use the generic as a default, and presumed consent laws allow them to assume that the patient agrees to the substitution. Both situations can be overruled by the patient. Using plausibly exogenous changes in states' laws, we use difference-in-differences and a discrete choice model to show that although the mandatory switching laws have little effect, the presumed consent laws reduce consumers' probability of purchasing brand name drugs by 3.2% points. The differential effectiveness of the laws is likely caused by pharmacists' profit motives. These results offer important implications for policies that seek to reduce drug expenditures by incentivizing the use of generic drugs.