Increased plasma 11-deoxycorticosterone during spironolactone medication.

The increase of plasma deoxycorticosterone (DOC) levels after administration of spironolactone is a real effect and not due to cross-interference of the drug or its metabolites with the DOC-assay. This is proved by in vitro and in vivo results. Of all the metabolites only canrenone interferes to some extent with DOC after liquid-liquid-extraction and paper chromatography. The antiserum, however, is so highly specific, that the final cross-interference of the total procedure amounts to less than 2% of the DOC plasma levels. Moreover, in patients with Addison's disease only a very small increase of DOC plasma levels can be observed after administration of spironolactone in contrast to normal subjects.