I am not aware of any medications that are specifically made for DID. The "parts" are us.

Having said that medications can made it harder for the my emotions to get anywhere near the surface so 'we' appear to be well. Speaking from my own experience high doses of Seroquel, klonopin and Lovan made 'the voices' go away. I hardly ever switched. I thought I was better but reversing the meds just saw the parts return. I was in a very secure emotional straight jacket but lose the meds and the voices came out to play again.

That's just my two cents worth and my own experience.