prescription drug costs

After listening to Senator Sanders on today's show it seems that few people are aware that, contrary to laws preventing people from buying their drugs from other countries, Walmart and several other major pharmacies purchase their prescription drugs from a manufacturer in India.  I read this company has a checkered history.  Congress passed the law against individuals going to Canada or Mexico because people had no guarantee that the drugs were safe for consumers.  But apparently commercial pharmacies can tell at a glance that the drugs they import from a manufacturer with a bad history are safe.