How can I translate medicines?

Any drug should list its chemical name or generic name, or searching up the brand name of the drug should tell you what it is. Then search the name on RXList, which contains a directory of brand drug names matched to generic names. Do note that brand names can vary in different markets; RXList primarily provides answers for US. Once you get the US brand name though, searching for other markets is usually easy.

Be very careful though substituting using this as dosage between brand names can vary, they might have other active ingredients blended in, etc. If you really aren't sure or comfortable doing all this, you're better off asking a pharmacist or a doctor for advice.

I look them up on the Internet. In the case of English I seem to be able to always find them in Wikipedia. Wikipedia will list the generic names and analogs as well as brand names and will also link to version of the article in various languages.

I jot down the names in the local language if I can find them, the generic and analog names, and if I have an empty box/bottle etc, I take that too.

I also try to tell them what my problem is and look at the chemical names on the things they show me because sometimes it's easier to spot them written than understand each other's accents.

I've had this fun the last year or so in both South America and Central Asia, heck, even Europe. I have several tablets, and they all have specific brand names. Of course at the pharmacy, apteka, apteek or whatever it's called in each place, even pronunciation varying slightly causes confusion - 'Warfarin' vs 'VarfarIn' is the difference between confusion and clarity(!).

I've found the best is to show them the previous meds box / container if you have it - as they may well recognise the brand name, and failing that, the 'generic' name. Or in one case in Uzbekistan, I went on Wikipedia and searched for the drug, and found what it was called over there.

Be sure to check the dosage though, as the concentrations can vary from country to country, and make sure to check it online afterwards if they give you something that seems a bit different - I had a doctor at a hospital in Tajikistan prescribe me something completely wrong - if I'd blindly followed their instructions I'd have ended up in hospital!

I know Ankur mentions the pharmacist or doctors - but seriously, in some of these countries their advice was shocking - offering me 'calcium' supplements instead of blood thinners, quite scary to see! Worst case, have the phone number of your GP on hand, as you can give them a call and get them to look it up and confirm that it's ok.

However most 'tourist' meds - headache, stomach etc are pretty common and standard everywhere and a simple headrub with pained face, or pointing to one's stomach will usually elicit the sympathetic look and the appropriate medicine for the area :)