Gregory's version of consciousness seems to be pretty causally important to me. After all, when your consciousness changes, you act like a totally different person!
So the story doesn't end up being about p-zombies, but is still pretty interesting. Or, perhaps, is interesting because it's not about p-zombies.
I thought some of you might enjoy this 2005 story published in Asimov's:
Second Person, Present Tense by Daryl Gregory (plus some of the author's notes on the story)
The story involves a a drug that (for a period of time) turns someone into a P-zombie.
It's currently available for free on the Asimov's page, but it may only be there temporarily.