My wife and I spent most of this summer in Mexico and were able to get controlled medications including zolpidem (comes in handy for those hard sometimes hard Mexican hotel beds when you need a good sleep) without proof of prescriptions. I'm sure the law might state you need a prescription but the reality is (from what we found) you walk into the pharmacy, you find the medication in their book on the counter, point to what you want, pay your cash and get what you want no questions asked.