There has been a study on fibromyalgia and spironolactone in the Scandinavian Journal of Pain by H. Wernze and Th. Herdegen: "Long-term efficacy of on pain, mood, and quality of life in women with fibromyalgia: An observational case series." Quite a strange study: no control group, no randomization, no end point, and moreover only a statistical analysis of responders. Perhaps I ask for too much, but I think putting patients under drugs should result in more than an "observational case series". I'm surprised that the authors got a positive ruling by their ethics committee. The authors concluded: "Fifteen of 31 women with otherwise treatment-resistant FMS experienced a number of prolonged beneficial effects from spironolactone on their complex pain-condition." They discussed: "Well-controlled, double-blind, and randomised trials are necessary to confirm our potentially very important observations." Very humble, indeed. They also discussed: "The high rate of non-responsive patients underlines that FMS may represent several subgroups." In this kind of studies you often find a hint at subgroups, but these haven't been defined yet. Perhaps it would be better, to define subgroups before starting giving drugs to patients.
I don't think that there will be coming much out of spironolactone in treating fibromyalgia. But I can't deny that there is this observation. If spironolactone in fibromyalgia is to be studied further, please only in a proper study.
PS.: PubMed didn't list any study, when I searched for it: