World Trade Organization (WTO) treaties between nations protect patents and trademarks. India is one of few nations that selected a protection scheme based upon protection of the manufacturing process (Process Patents) rather than using the more common scheme of protecting the actual product (Product Patents).
As a result, Indian pharmaceutical chemists can legally create, by reverse engineering, and sell worldwide, drugs that are still patent protected elsewhere if they do so using a process that creates the identical drug through the use of a different process.
Therefore these drugs can be marketed at prices that reflect their real manufacturing cost, rather than a monopoly price that is set without regard to competition and regain the great cost of research and development, and advertising and promotions to doctors and the US public.
In addition India has very strict price controls ( the same as Canada )on the retail selling prices of drugs, and this keeps Indian pharmacies from being able to raise their prices higher than these limits.
Indian Patent law has a quirk that under international law, allows scientists there to reverse engineer the active molecule of brand name drugs using a different process than the original patent to do it, and obtain a process patent of their own on the new process.
Indian Drugs, legally made and patented, without huge development and advertising costs are legal for sale worldwide, at a fraction of the cost of the name brand they duplicate, and that is why our prices are low, and is the cause of the huge controversy about the importation of drugs to the U.S.
The result is that India has become the largest producer of generic drugs in the world, with a quality that meets all health and medical standards.
US companies have spent billions in advertising to convince you that brand and generic drugs are not the same, although their use is encouraged by AARP, so now you know the actual facts.
This is very similar to the way actors use a stage name. Just as the actor is one person with two names, these drugs are one chemical with two names.
Stage names and brand names serve the same purpose, and that is to identify them deeply in the mind of the public, to make them easy to remember. Both refer to one actor, or one drug. So, Tony Curtis and Bernard Schwartz are the same actor, two names.