Seven states and Washington, D.C., required patients to consent to substitution, while 23 states found that patients had the right to refuse substitution without having to consent. When the substitution was made, 31 states and Washington, D.C., required patients to be informed of the action, regardless of the packaging of the drug. As a retailer in one of the most regulated industries in the United States, a pharmacist must adhere to strict regulations in their distribution behavior, including their generic distribution actions. At one time, most state laws required pharmacists to fill a prescription as written, which prevented generic drugs from dispensing if the doctor had written the brand name. The last of these anti-substitution laws was repealed in 1984. In 2009, generic drugs accounted for 74.5% of U.S. retail prescriptions, up from 18.6% in 1984 (Berndt and Aitken, 2011). “Our results show significant scope for optimizing state drug selection laws to promote generic, interchangeable biologic substitution,” Sacks and colleagues wrote. Results This cross-sectional analysis of generic substitution regulation in all 50 U.S. states and Washington, D.C., found that for small molecule drugs, 19 states required pharmacists to perform generic substitution; 7 states and Washington, D.C., required patient consent; 31 states and Washington, D.C., have mandated patient notification regardless of the packaging of the drug, and 24 states have not specifically protected pharmacists from greater liability. Nine states and Washington, D.C., had a generic surrogate value for small molecule drugs of 3 or more, and 45 states had stricter requirements for interchangeable biologic substitution, most commonly mandatory medical notification. It is essential that the estimated selection model includes reasonable models of product substitution. Our model predicts that the price elasticity is between -0.005 and -0.09, which is lower than estimates in recent literature (Simonsen, Skipper and Skipper 2016).
The differences most likely result from our model specification, which calculates price elasticity based on purchase. Adding an external no-purchase option would result in higher estimates of price elasticity. In addition, our model shows significant molecular substitution. When the OPP of a brand name drug increases by one percent, the majority of consumers who switch choose to stick with the same molecule. Previous research has linked generics to improved adherence and health outcomes, wrote Chana A. Sacks, MD, a member of a regulatory, therapeutic, and legal program in the Department of Medicine at Brigham and Women`s Hospital, and colleagues. They added that greater consistency in surrogate laws across states “could reduce health system spending [and] improve population health.” Figure 2 shows the generic substitution score assigned to each state and Washington, DC. Thirteen states (Arizona, Illinois, Kentucky, Massachusetts, New Jersey, New York, North Carolina, Oklahoma, Rhode Island, Tennessee, Washington, Wisconsin, and Wyoming) had values between 0 and 1, reflecting few restrictions on generic substitution of small molecule drugs. In contrast, 9 states (Alaska, Arkansas, Connecticut, Iowa, Louisiana, South Carolina, Texas, Utah, and Virginia) and Washington, D.C. had scores of 3 or higher, indicating greater barriers to generic substitution. Bioavailability tests are used to determine whether a drug has the same effect as a generic equivalent.
Bioequivalence can be determined by one of four mechanisms: pharmacokinetic studies, pharmacodynamic studies, comparative clinical studies or in vitro studies. The last three elements above are used to test drugs in which plasma concentrations are not affected, such as nasal sprays, aerosols, and topical drugs.3 Pharmacokinetic studies test bioequivalence by measuring plasma concentrations to determine the rate and extent of absorption. These tests are performed with 24 to 36 volunteers, and single doses of test and reference drugs (or standard or innovative) are administered. If two drugs containing the same active chemical unit reach the absorption site in a similar time and can be absorbed to the same extent, bioequivalence can be established. Bioequivalence ranges measured by pharmacokinetic parameters range from 80% to 125%.4 This means that products are considered bioequivalent and likely therapeutically equivalent if the generic version of the reference product has a 20% lower absorption or up to 25% absorption. Most pharmacists already know that the Orange Book, created in 1980 and now in its 28th edition, is an FDA publication that lists many drugs and provides clues as to whether generic versions of drugs are considered “equivalent” to drugs manufactured and most often marketed with brand names by the innovator. However, pharmacists may not realize the inherent limitations of criticism of the Orange Book. What is commonly referred to as the Orange Book is actually entitled Authorized Drugs with Therapeutic Equivalency Assessments. (In the days when books were only published in bound format, this text was bound with an orange cover, hence the popular name; in the age of Internet publications, the online version is usually referred to as the Orange E-Book.5 ) One of the most important limitations of this federal publication stems directly from the first part of its official name: Approved Drugs. The only drugs listed in this book are those that have been approved by the FDA as so-called new drugs.6 The FDA does not list drugs that are on the market without a new drug approval (NDA).