You and I define monopoly very differently. As a matter of fact, I think you'd be hard pressed to find many others who define the term in the same manner you do. Good deals are available in other countries simply because the drug companies are forced to sell their products in those countries under strict price controls. This creates a false economy - not an open market as you suggest - and is in no way akin to buying apples from Chile in any supermarket.
In almost all of the agreements that these parasitic countries sign with the drug companies, they agree not to resell the drugs to other countries. This portion of the agreement is never enforced so it is very understandable why the drug makers are upset and lobby congress for assistance. The bad guys here are the nanny states who get to enjoy the many benefits the pharmaceutical companies provide while demanding that others pay for it. How you can misconstrue this situation into somehow creating a monopoly for the drug makers is a mystery.
A great many companies price differentially in different countries, simply because what the traffic will bear differs from one country to another. You will sometimes see American textbooks appearing in discount bookstores, marked "For sale in Canada only", because that condition was a part of the sales deal between the American publisher and a Canadian distributor. If the textbook printer sees that too many books are "leaking" back to the US market in this manner, his recourse is simply to stop selling to the Canadians. The Canadian distributor would then lose that particular chunk of US trade.
What's different about the drug companies is they, and they alone, get US government help in enforcing their sales agreements in foreign countries. It's specifically illegal in the US to have your prescriptions filled in other countries. The US will look the other way for such leaks as personal purchases by Americans who physically travel to Mexico and get scripts filled on the border. But everyone knows that there can be a crackdown at any time, as there recently has been on purchases from Canadian pharmacies.
You seem to feel that pharma companies have some sort of special moral right in making Americans bend over and take this monopoly pricing scheme. I don't, and I take great pride in dealing with your "parasitic countries" whenever I can. Mexico is less than a day's drive from my place, and New Zealand is becoming the "new Canada" on the Internet. In an era when they can send my job to India whenever they feel like it, why don't I have the same right to outsource my prescription purchases?
I suggest you call your doctor and have him cancel your prescription for Kool-Aid, pronto.