It's called a 'patent'. US laws prevent importing of patented drugs. You have to understand that the production cost of most drugs is near zero. Almost all of the cost is in the FDA approval process. US drug manufacturers must price their products to recover that cost, as well as the costs of drugs that are not approved. They can also make a little profit from selling their products in price controlled countries outside the US. These prices are far below what the price would need to be to recover their FDA approval costs. So they price their drugs in the US to recover their US approval costs, and they price their products in other countries to make a little profit. Allowing reimportation of these drugs would eliminate the chance of recovering their FDA approval costs.
Once the patent expires (which is usually only a few years after the FDA approval is granted), all this goes away, because the FDA approval process also requires them to tell exactly how they make the drugs, so anyone can make them once the patent expires.
“...You have to understand that the production cost of most drugs is near zero. Almost all of the cost is in the FDA approval process...”
Oh, I understand it just fine. But the effect is the same. Sell to a captive market that is artificially denied access to other valid markets licensed by the same Pharma manufacturer and source govt. That smells like monopoly to me, whether it’s induced by govt or Pharma makes no difference to the consumer.
Once upon a time, a patent was used to constrain the manufacture, sale or use in the manufacture or sale of a product — not to prevent the *consumer* buying from an otherwise perfectly valid, licensed manufacturer or seller. If the consumer bought the drug from an unlicensed seller/manufacturer, the patent holder (and the govt) should have a problem with the unlicensed seller/manufacturer, not the consumer. But that’s not how it works, is it? Hence, artificial monopoly, “patent”, whatever you want to call it.