I found this very interesting thread today
Some of the information is not very good however. Possessing controlled substances (Lomotil, Ambien are examples cited in that thread) without a prescription (or in the original prescribed container with your name on it) may land you in jail in the US (and many other countries).
While containers add bulk, many pills are available in marked blister packs which - along with a photocopy of your prescription - will suffice to keep you legal, but a jumble of loose pills in a bottle are a 'prescription' for trouble at a TSA checkpoint or CBP point of entry.
You need to comply with the rules of the country in which you have the drugs. Just because I can buy Lomotil across the counter in another country doesn't make it legal to possess that drug without a prescription in a country that controls that drug.
When in trouble, obfuscate.