Troglitazone induces CYP3A4 activity leading to falsely abnormal dexamethasone suppression test.

摘要: After evaluating a patient who appeared to have falsely abnormal response the dexamethasone suppression test while taking troglitazone, we examined effects of troglitazone on activity hepatic CYP3A4 and screening tests for Cushing's syndrome. We studied five healthy women three men, aged 25 +/- 2 yr, before after treatment with (600 mg daily) 28 d. Baseline 0800 h cortisol corticosterone were similar treatment. Before treatment, all subjects suppressed below 1.8 micro g/dl (mean, 0.66 0.08 g/dl) during 1-mg overnight (DST), whereas none 9.0 g/dl). Serum levels decreased by 66 4%, erythromycin breath measurements increased 27 8%, indicating The hydrocortisone (HST) was performed administering 50 at 2300 h. Using criterion plasma more than 50%, specificity HST 100% both In conclusion, induced leading DST. is useful alternative DST in patients medications that increase CYP3A4.