Ten psoriatics were tested with three concentrations of
butantrone (0.66, 2.0 and 3.9%) on the healthy skin of the back and the
irritant and staining reactions were compared with those produced by 0.1 and 0.5%
dithranol, both in
white petrolatum. Of the three test areas one was stripped before exposure to simulate the penetration of a
psoriasis lesion, one after exposure to simulate posttreatment washing and one was unstripped. The contact times were 20 and 60 min. The degrees of
erythema and staining, and the increase in skin blood flow were measured 1, 2, 3 and 7 days after application. Both
dithranol concentrations produced a markedly stronger increase of blood flow and
erythema than any of the
butantrone concentrations and a clear dose response when the concentration was raised from 0.1 to 0.5%. Such a dose response was not clearly seen with
butantrone. Staining with both
dithranol and
butantrone was minimal. Apparently, higher concentrations of
butantrone than
dithranol can be used in short contact
therapy if cumulation of the
drug can be excluded by a short contact time and careful removal of the surplus
drug.