Cushing's syndrome due to pharmacological interaction in a cystic fibrosis patient

Abstract

This observation suggests that the metabolic clearance of buDesonide was compromised by itraconazole's inhibition of cytochrome P450 enzymes, especially the CYP3A isoforms, causing an elevation in systemic budesonide concentration. This provoked a complete suppression of the endogenous adrenal function, as well as iatrogenic Cushing's syndrome. Patients on combination therapy of itraconazole and budesonide inhalation should be monitored regularly for adrenal insufficiency. This may be the first indicator of increased systemic exogenous steroid concentration, before clinical signs of Cushing's syndrome emerge.