An unusual cause of growth failure in cystic fibrosis: A salutary reminder of the interaction between glucocorticoids and cytochrome P450 inhibiting medication.

A 12 ½ year old male with cystic fibrosis presented with growth failure after itraconazole was added to a treatment regimen including inhaled and intranasal glucocorticoids. Investigations showed severe adrenal suppression. This case demonstrates the potential for exogenous glucocorticoids to accumulate when their degradation is inhibited by a CYP3A4 inhibitor.