the dominican republic is one of many countries where people are allowed to determine for themselves their medications (not all, but many). many Americans take advantage of this and buy quantities of their prescriptions when there to take advantage of the savings. Don't see why Rush would bother other than since his records have a way of becoming public knowledge, he may have decided that he didn't want the press to know he used Viagra.
I would be just fine with people keeping something like that private. In fact, I would prefer it. I wish Bob Dole had.