Looking for "The Yellow Pill"

Anyone hear of a short story called “The Yellow Pill”?

It was a short story that I read in HS. It was a strory about two guys in a space capsule. One was “sane” and begged his partner to take a yellow pill. But his partner was insane and thought the other was just trying to kill him.

It was a really cool story about the relativity of sanity; each person thought the other was insane.
Any help would be greatly appreciated.

I googled it and came up with the author Rog Phillips, which was a pseudonym of Roger Phillip Graham. Does that help?

http://www.locusmag.com/index/s581.html#A13682