I flew with my pills, all in their little labelled bottles. As I was staying in private accommodation most of the time, their security was not an issue for me--- I leave that to others for suggestions. I also scanned my prescriptions and saved them as attachments in my draft email file folder, so that in case of refills or losses, I could simply get refills in Spain. I come from a pharmaceutical family and was impressed by Spanish pharmacies and their staff, who run a tight ship. Most medicine is now produced by large international pharmaceutical companies and it is likely that your medicine is produced by them, and will be available in Spain. I also suggest that, if you have a complex medical situation, have your GP draw up a protocol (i.e., identifying condition, treatment, and medications) and have it translated into Castilian by a professional medical translator (this will cost you $100--$200, but if there is an emergency, will be worth every cent). Carrying a list of your prescription medications in your wallet will also assist medical staff should you fall ill-- there are a number of situations where this could be helpful-- e.g., symptoms of diabetes can sometimes be mistaken for drunkenness.