Abstract
Dexamethasone suppression tests are basic tools in diagnostics of
hypercortisolemia. Low-dose tests play major role in screening and initial
assessment. High-dose tests are aimed at more elaborate diagnostics, however
their clinical value is questionable. Dexamethasone is a highly potent,
synthetic steroid. It is metabolized by cytochrome P450 3A4 (CYP3A4), and so are
various other xenobiotics. Due to wide spectrum of substances processed by
CYP3A4, interferences and interactions are not uncommon. Physicians should be
familiar with drugs modifying dexamethasone metabolism, and therefore the
results of dynamic tests. Other important concerns are: drugs enhancing
cortisol-binding globulin production, organ dysfunction, pseudo-Cushing states,
pregnancy and other physiological conditions leading to elevated blood cortisol,
cyclic Cushing disease. To properly assess and assist patients, it is crucial
for health professionals to understand and be able to overcome such clinical
dilemmas.
Key words
hypercortisolemia - Cushing’s syndrome - glucocorticoids - dexamethasone - dexamethasone suppression test - hormonal testing