Isn't it alreday an international currency? I think it is. Since people around the world begun to use it it has begun global, international currency. Today I think it is used on all continents. Will it be officialy recognized as such, that is another question.
The international currency or a global currency is the currency that worth in all countries and has a user covers the entire country? if viewed bitcoin you would see users from different countries? and bitcoin has a price in every country because I believe bitcoin can exchange in local currency? it means that bitcoin has become a global currency