Good question, Quantumsaint!

While their effect is similar, these are not the echo drops that appear in other games in the FINAL FANTASY series. The good man in charge of items for XIV decided way back before beta that he wanted to give different names to the antidotes currently in the game. When localizing the items, we decided to go with names that represented which part of the body they cured. Silence (in theory) affects the vocal chords, therefore "throat drops" seemed a good representation of what we believed the people in Eorzea would call such a medicine.

This isn't to say that echo drops, gold needles, and all those other nostalgic curatives won't be making their way into the game sometime in the future.