1: Int J Tissue React. 1988;10(2):115-9.Links
Topical spironolactone inhibits dihydrotestosterone receptors in human sebaceous glands: an autoradiographic study in subjects with acne vulgaris.
Berardesca E, Gabba P, Ucci G, Borroni G, Rabbiosi G.
Department of Dermatology, University of Pavia, Italy.
The interaction between spironolactone and dihydrotestosterone (DHT) receptors was evaluated with an autoradiographic technique. The inhibition of DHT receptors by spironolactone was found to be related to the decrease of tritiated DHT granules in the sebaceous glands of the treated site. 6 male patients affected by acne vulgaris entered the study. The acute study was performed by applying to 25 cm2 of the back a cream containing 5% spironolactone under occlusive dressing. The dosage of spironolactone applied was 4 mg/cm2 for 48 h. The long-term study was performed by applying the same amount to the entire back, without occlusion, twice daily for 1 month. Skin biopsies were taken at the end of the treatment, incubated with tritiated DHT and processed for autoradiography. Both the acute and the long-term study revealed a decrease of the autoradiographic granules in the treated site. This effect is related to the binding of spironolactone with dihydrotestosterone receptors in the sebaceous glands. Our study demonstrates that 5% topical spironolactone cream acts as an antiandrogen in human sebaceous glands, competing with DHT receptors and producing a decrease of labelled DHT. At the concentrations used the effect has been only local. No side-effects were recorded during both studies.
Rey, F. O., C. Valterio, et al. (1988). "Lack of endocrine systemic side effects after topical application of spironolactone in man." Journal of Endocrinological Investigation 11(4): 273-8.
Abstract: "In six healthy male volunteers, the percutaneous absorption of spironolactone was compared with placebo in a double-blind crossover study. The subjects were randomly given either a cream containing 5% spironolactone or placebo to be applied in a randomized sequential way to a well defined skin area equivalent to 55% of body area. [my emphasis] During the 72 h following the application of the ointment, blood levels of canrenone, the major metabolite of spironolactone, have been determined. In order to estimate the systemic antiandrogenic effect of spironolactone, plasma levels of 17-alpha-Hydroxy progesterone (17 alpha-OH-P), Testosterone (pT) and non-conjugated 3 alpha-Androstanediol (3 alpha-diol, metabolite of the active androgen 5 alpha-Dihydrotestosterone or DHT) as well as salivary Testosterone (sT) which relate to the free and active plasma testosterone fraction have also been measured. Urinary levels of canrenone have been determined 48 hours after cream application. No changes in any levels of these hormones have been detected and plasma canrenone levels were undetectable during the 72 hours of topical treatment. Topically administered, spironolactone appears to have only a local skin impregnation."
In summary, subjects essentially bathed in either a 5% spironolactone cream or placebo (vehicle only) in a controlled manner, and there was no evidence of percutaneous (systemic) absorption.
Countries in which topical spironolactone is commercially available as an "official" treatment for acne in both males and females have also consistently reported its absence of systemic effects. E.g.,
Messina, M., C. Manieri, et al. (1990). "Oral and topical spironolactone therapies in skin androgenization." Panminerva Medica 32(2): 49-55.
Abstract: "The most important clinical studies using spironolactone as an antiandrogen drug either per os or topically are referred. Menstrual disturbances very often occur during SP treatments thus limiting its systemic use. As far as the topical use is concerned SP seems to be highly effective with absence of systemic effects. Local mild side effects were present in a small number of patients."
Yamamoto, A. and M. Ito (1996). "Topical spironolactone reduces sebum secretion rates in young adults." Journal of Dermatology 23(4): 243-246.
Abstract: "The effects of topically applied spironolactone on the sebum secretion rates (SSR) of young adults were investigated. SSR was expressed as the ratio of wax esters/(cholesterol + cholesterol esters) (WE/(C + CE)) and the amount of sebaceous lipids (squalene, triacylglycerol and wax esters). Topical spironolactone 5% gel applied to the right cheeks of the subjects produced a significant reduction in the SSR at 12 weeks (4 weeks after termination of application), but not at 8 weeks (the end of treatment). Untreated "control" areas (the left cheeks of the subjects) showed no significant change during the study. None of the subjects experienced skin rash or signs of local irritation. This results suggests that topical spironolactone may be effective in the treatment of acne patients with high SSR."