The FDA requires drugs that are sold in the United States to be manufactured in the United States. So all the large drug companies have factories in Puerto Rico, where they can get inexpensive labor. The drugs that are manufactured in Puerto Rico go the United States and to most other places in the world, including Canada. The drugs that are sold in Canada are exactly the same as those sold in the United States, there is no difference. The reason that Canadian drugs are cheaper is because it is cheaper to sell things in Canada, there is not as much red tape and litigation. The reason that drugs are more expensive in the United States is because Americans can afford to pay more.