Looking for strange story published in the 60s or 70s, possibly early 80s (less likely)

[pwalsh]

I once read a story in a digest sized magazine about a writer who drank Listerine or something similar as a way to inspire himself to write--it transported him to another world, and he wrote about the goings on there--mostly the actions of a couple he could see from the tower to which he was transported. I think it had an O.Henry type ending--he needed the bottle to get to and from the tower, and he dropped it or something that effect, trapping him there forever, I think.

Anyone remember that one?

Thanks!

Philip