A coworker who worked as a doctor in Afghanistan and Myanmar for about a year told me that a third of the medications they had in the hospital, and two thirds of the medications you could purchase in pharmacies contained no active ingredient. People kept dying on him because an antibiotic would randomly do nothing, or lysis medication turned out to consist of colored NaCl. He said that most of those medications were delivered from China and India because of the low prices in those countries. This is anecdata, obviously, but I'd be very careful purchasing drugs from countries with low oversight. Fake drugs are an enormously profitable market.

I also like this quote from a New York Times article:

“If I have to follow U.S. standards in inspecting facilities supplying to the Indian market,” G. N. Singh, India’s top drug regulator, said in a recent interview with an Indian newspaper, “we will have to shut almost all of those.”

The unease culminated Tuesday when a top executive at Ranbaxy — which has repeatedly been caught lying to the F.D.A. and found to have conditions such as flies “too numerous to count” in critical plant areas — pleaded with Dr. Hamburg at a private meeting with other drug executives to allow his products into the United States so that the company could more easily pay for fixes. She politely declined.

http://www.nytimes.com/2014/02/15/world/asia/medicines-made-...

There may be requirements to purchase the drug from manufacturers that comply with government regulated quality controls.

Not that someone who really needs the drug couldn't seek out an online source to get it cheaply from overseas, but doctors may not be able to legally prescribe it from those places.

I don't have any knowledge on the subject though, just speculating. At least in the US buying directly from overseas pharmacies seems to be more or less illegal.

"doctors may not be able to legally prescribe it from those places."

We just get a prescription and have it filled wherever's cheapest. It's not up to the doctor to say where it can be filled...

It may be illegal for pharmacies operating in Canada to buy from those manufacturers then, I don't know. I'm just saying there are possible additional risks with buying drugs of unknown provenance. It's not necessarily as simple as "just buy it from China or India".