To get a drug certified for sale in the US the manufacturer must agree to supply a certain amount to price controlled economies like India and Canada. In exchange they get to charge Medicare or US insurance companies whatever they want. The reason drugs like common heart medications are in short supply in places like Canada is that the pharmacies that get them in Canada can resell them at a higher price to Americans than they are allowed to charge in Canada. Thus, they all get sold on the Internet leaving Canadians wanting. When you get those drugs, yes, it’s a great deal when compared to the artificially supported US price, but it means the country you get them from will run out quickly.
This happens to any price-controlled commodity. You’d think governments would know this, but they do it anyway because...politics.
Why don’t the pharma companies just make more?
India ,manufactures a lot of drugs we use here, and they are dirt cheap there.