Date of report 02 Sep 2021

Reported case interaction between
Ritonavir and Fluticasone

A 45-year-old HIV infected African-American woman was seen for evaluation of goiter. The patient presented with a cushingoid appearance. Her medical history included asthma, hypertension and obstructive sleep apnea. The patient's clinical picture was compatible with a Cushing Syndrome. A diagnosis of adrenal insufficiency was also established. The patient was initiated on hydrocortisone (10 mg twice daily) and fluticasone (nasal spray and aerosol) was stopped due to a suspicion of drug-drug interaction with darunavir/ritonavir. The symptoms of Cushing Syndrome improved over several months after stopping fluticasone. An ACTH stimulation test was normal indicating recovery of adrenal function. However, the patient developed non-PTH mediated hypercalcemia. A DEXA scan demonstrated osteopenia. While the etiology of hypercalcemia remained unclear, new symptoms of hip pain developed. MRIs of both hips revealed bilateral avascular necrosis of the right hip necessitating hip replacement. Since the patient developed non-PTH mediated hypercalcemia after adrenal function returned to normal, hypercalcemia was deemed secondary to avascular necrosis. Serum calcium normalized over the next few months and both Cushing syndrome and adrenal insufficiency had resolved. The non-PTH mediated hypercalcemia and avascular necrosis of the hip were likely the complication of iatrogenic Cushing Syndrome caused by the interaction between darunavir/ritonavir and fluticasone. This case has been published by Kant R et al. in Cureus 2020; 12(8):e9644.