Abnormal suppression of plasma cortisol during the intravenous infusion of dexamethasone to alcoholic patients.

In some cases the oral administration of dexamethasone to alcoholic patients has failed to cause a normal depression of plasma cortisol levels. Although alcoholics often show signs of intestinal malabsorption, the possibility that the dexamethasone was not fully absorbed has not previously been considered. To eliminate any question of malabsorption, ten male alcoholic patients were infused intravenously with dexamethasone (1 mg/h). The plasma cortisol levels in blood samples withdrawn at half-hourly intervals during a 2-h infusion were compared with the values found in ten normal subjects similarly infused. Four of the alcoholics failed to show normal suppression of plasma cortisol levels, thus confirming that in some alcoholics there is a disturbance of pituitary-adrenal function similar to that found in Cushing's disease. In only one of the four cases was failure to suppress normally associated with the presence of clinical signs of Cushing's disease.