[Testing the loss of efficacy (tachyphylaxis) during external steroid application].

The steroids fluprednylidene-21-acetate (FA) and betamethasone-17-valerate (BV) were tested in comparison to their inactive bases for loss of activity (tachyphylaxis) after 2 weeks of application. In the croton oil test, both steroids produced equal inhibition of the pustular inflammatory reaction. The vasoconstriction test after 14 days of use revealed a clear decrease in the blanching reaction - which was, however, not statistically significant in the case of BV.