Are placebo-controlled trials of creams for athlete's foot still justified?

Background Placebo-controlled trials are useful in identifying effective treatments where none has existed, but their continued use once efficacy is established arguably contravenes ethical standards for medical research. Objectives To consider whether sufficient evidence exists to recommend the abandonment of vehicle-controlled studies in trials of topical treatments for athlete's foot. Methods We searched nine electronic databases and bibliographies of review articles as part of an ongoing Cochrane systematic review from 1966 to 2007. Randomized controlled trials (RCTs) using a vehicle control design involving participants with a mycological diagnosis of a dermatophyte infection of the skin of the foot were included. Results Allylamines, azoles, ciclopiroxolamine, tolnaftate, butenafine and undecanoates were all more effective than vehicle controls. Evidence of the superiority of azole creams over vehicle controls was fairly consistent from 1975 onwards. Data from patients treated with allylamines have shown their superior effects relative to vehicle controls since 1991 for even short-term outcomes. Conclusions The superiority of allylamines and azoles over vehicle in vehicle-controlled trials has been well established, and data demonstrating this fact have been available since the completion of early RCTs. These preparations are effective and safe, and investigators of RCTs evaluating topical treatments for athlete's foot need to choose potential comparators as control interventions in the light of this knowledge and to consider the ethics of withholding effective treatment from patients who seek treatment for this common foot infection.