I know exactly what you are talking about. I've studied abroad many times and brought back medications. I lived in Poland and had Valium prescribed for anxiety on the plane. They just give you the box when you get a prescription. There is nothing for you to declare, declaration is for the purpose of taxation. I have been worried before because I get a lot of my meds in samples, which obviously don't have my name on them, but if a medication is prescribed to you, it's prescribed to you. They don't question this anywhere in Europe or Eurasia and I have never had a problem returning to the US with meds in their original packaging (without a the "prescription label" we get in the US). I think by now customs is aware that this is just about the only place in the world where prescriptions are dispensed in special bottle with labels containing the patients' information. My rule of thumb on returning from study abroad has always been:
1. Take your nose ring out before going through customs.
2. Declare your liter of spirits and carton of smokes.
3.Keep your mouth shut until they say "Welcome Home," then remember English and say "Thank you."

I am on a variety of meds and have a LOT of stamps in my passport. Nobody cares about medicine.