Re:Customs
When I lived outside of Yuma,AZ we used to go to a little border town called Los Algodones to purchase meds. Most controlled substances(narcotics) require a prescription. If you have a US prescription take it, they will accept it. It would also reduce the risk(very, very small risk) of having trouble @ customs. As stated before there is usually a Dr around to write an RX but it is my experience that they usually charge a fee to write an RX for a narcotic(PV could be different than the border towns tho).