after patents expire by allowing another company to sell an authorized generic; a 2011 ftc report found that consumers benefitted from lower costs when an authorized generic was introduced during the 180 day exclusivity period, as it created competition. innovator companies may also present arguments to the fda that the anda should not be accepted by filing an fda citizen petition. the right of individuals or organizations to petition the federal government is guaranteed by the first amendment to the united states constitution. for this reason, the fda has promulgated regulations that provide, among other things, that at any time, any "interested person" can request that the fda "issue, amend, or revoke a regulation or order," and set forth a procedure for doing so. acceptance some generic drugs are viewed with suspicion by doctors. for example, warfarin (coumadin) has a narrow therapeutic window and requires frequent blood tests to make sure patients do not have a subtherapeutic or a toxic level. a study performed in ontario showed that replacing coumadin with generic warfarin was safe, but many physicians are not comfortable with their patients taking branded generic equivalents. in some countries (for example, australia) where a drug is prescribed under more than one brand name, doctors may choose not to allow pharmacists to substitute a brand different from the one prescribed unless the consumer requests it. fraud a series of scandals around the approval of generic drugs in the late 1980s shook public confidence in generic drugs; there were several instances in which companies obtained bioequivalence data fraudulently, by using the branded drug in their tests instead of their own product, and a congressional investigation found corruption at the fda, where employees were accepting bribes to approve some generic companies' applications and delaying or denying others. in 2007, north carolina public radio's the people's pharmacy began reporting on consumers' complaints that generic versions of bupropion (wellbutrin) were yielding unexpected effects. subsequently, impax laboratories's 300 mg extended-release tablets, marketed by teva pharmaceutical industries, were withdrawn from the us market after the fda determined in 2012 that they were not bioequivalent. problems with the quality of generic drugs – especially those produced outside the united states – are widespread as of 2019. the fda does infrequent – less than annual – inspections of production sites outside the united states. the fda normally gives advance notice of inspections, which can lead to cover-ups of problems before inspectors arrive; inspections performed with little or no advance notice have produced evidence of serious problems at a majority of generic drug manufacturing sites in india and china. litigation two women, each claiming to have suffered severe medical complications from a generic version of metoclopramide, lost their supreme court appeal on june 23, 2011. in a 5–4 ruling in pliva, inc. v. mensing, the court held that generic companies cannot be held liable for information, or the lack of information, on the originator's label. india main article: pharmaceutical industry in india the indian government began encouraging more drug manufacturing by indian companies in the early 1960s, and with the patents act in 1970. the patents act removed composition patents for foods and drugs, and though it kept process patents, these were shortened to a period of five to seven years. the resulting lack of patent protection created a niche in both the indian and global markets that indian companies filled by reverse-engineering new processes for manufacturing low-cost drugs. the code of ethics issued by the medical council of india in 2002 calls for physicians to prescribe drugs by their generic names only. india is a leading country in the world's generic drugs market, with sun pharmaceuticals being the largest pharmaceutical company in india. indian generics companies exported us$17.3 billion worth of drugs in the 2017–18 (april–march) year. in 1945–2017, bioequivalence studies were only required for generics of drugs that are less than four years old. since 2017, all generic drugs of certain classes, irrespective of age, require bioequivalence to be approved. china main article: pharmaceutical industry in china generic drug production is a large part of the pharmaceutical industry in china. western observers have said that china lacks administrative protection for patents. however, entry to the world trade organization has brought a stronger patent system. china remains the largest exporter of active pharmaceutical ingredients, accounting for 40% of the world market per an 2017 estimate. bioequivalence studies are required for new generic drugs starting from 2016, with older drugs planned as well. in addition, in vitro dissolution behavior is required to match. since 2018, 44 classes of drugs are exempt from testing (requiring only a dissolution check), and 13 classes only require simplified testing. industry as of 2021, several major companies traditionally dominate the generic drugs market, including viatris (merger of mylan and upjohn), teva, novartis' sandoz, and sun pharma. prices in traditional generic drugs have declined and newer companies such as india-based sun pharma, aurobindo pharma, and dr. reddy's laboratories, as well as canada-based apotex, have taken market share, which has led to a focus on biosimilars.