Matters of the HAART: Ritonavir Induced CYP3A4 Inhibition of Intranasal Fluticasone Leading to Cushing's Syndrome

The article discusses a case where a 57-year-old man with HIV on HAART developed Cushing’s syndrome due to the interaction between ritonavir, a potent CYP3A4 inhibitor, and over-the-counter intranasal fluticasone propionate (FP). Despite not using oral or topical steroids, the patient experienced symptoms like fatigue, weight gain, and easy bruising. Physical examination and lab results confirmed exogenous steroid-induced Cushing’s syndrome. The condition resolved after discontinuing FP. The study highlights the importance of educating patients on ritonavir about the risks of using OTC steroids and the need for thorough medication reviews to prevent such adverse effects.