"What is preventing legislation that simply opens borders / trade for filling prescriptions?" US suppliers sell to Canada at a different price than they sell i

"What is preventing legislation that simply opens borders / trade for filling prescriptions?" US suppliers sell to Canada at a different price than they sell in the US. If 'borders were open' - the price in US would go down, the price in Canada would go up, roughly to the same price. I understand that it seems odd, but I reject the idea that it's 'corrupt' to sell to one country at a different price than another. Drugs are essentially IP, so it would be like the US selling Canada the 'Superbowl' and then Canada selling and broadcasting it to the rest of the world at a discount. I think something should be done about that - but drugs are not like most goods. And of course, many goods have different controls and regimes. Another aspect: it's not really 'free trade' when a government entirely regulates the economy for a good. So when gov of Canada 'sets prices' for a good, it kind of flies in the face of regular trade rules and potentially gives one side or another advantages, so it really doesn't fit well under things like WTO or NAFTA. Surely we could have some new thinking about this though ...