This is certainly not an area I'm an expert in, but the answer appears to be techinically "yes" but with little risk on individuals who do so. The main concern the Food & Drug Adminstration has with buying prescriptions drugs from foreign countries is that their quality can't be verified. Here are a couple of links that may provide more information:
http://www.fda.gov/importeddrugs/
http://www.fda.gov/ora/import/kullman.htm