Carbamazepine and falsely positive screening tests for Cushing's syndrome
Tiong, K.; Falhammar, H.
New Zealand Medical Journal 122(1288): 100-102
2009
ISSN/ISBN: 1175-8716 PMID: 19182847 Document Number: 632486
A case of markedly elevated 24-hour urine-free cortisol levels, mainly due to interference with carbamazepine when measuring with high performance liquid chromatography but also due to increased fluid intake, is presented. Moreover, the 1 mg overnight dexamethasone suppression test was positive and the midnight serum cortisol level was slightly increased, probably as a result of carbamazepine-induced activity of CYP3A4 and increased levels of cortisol binding globulin.