Not sure what this is, or if it is even real as I am not an ancient guy. A friend's dad got it a long time ago and I was asked about it.
Sadly, it is not a genuine ancient coin.
It is a brass replica of a silver tetradrachm of King Antimachus I, from the ancient kingdom of Bactria, which was located in what we now call Afghanistan. You can compare your coin with genuine silver examples on this Wildwinds page: http://www.wildwinds.com/coins/greece/baktria/kings/antimachos_I/t.html
Large numbers of base-metal Bactrian replicas like this were sold as souvenirs to Westerners while the Western intervention was in Afghanistan. I guess now the Westerners have mostly packed up and left, the replica-makers are having to find other work.
Thanks so much for the detailed info! Appreciate it a bunch.