Fluticasone-propionate/ritonavir interactionCushing's syndrome and avascular necrosis of shoulder: case report A 51-year-old man developed Cushing's syndrome and avascular necrosis of shoulder during concomitant treatment with fluticasone-propionate for chronic allergic rhinosinusitis and ritonavir for HIV infection [not all routes stated; dosages not stated].The man with HIV infection, had been receiving treatment with ritonavir. He presented with one year history of bilateral, temporal headaches. It was reported that two years before, he started receiving treatment with intranasal fluticasone-propionate [fluticasone] spray for his chronic allergic rhinosinusitis. In the following months, he developed lethargy, weight gain, a plethoric face and abdominal striae. Subsequently, he was diagnosed with drug-induced Cushing's syndrome. Also, he developed avascular necrosis of shoulder, which was precipitated by his hypercortisolism. Based on these clinical presentations, it was concluded that he developed Cushing's syndrome and avascular necrosis of shoulder due to an interaction between fluticasone-propionate and ritonavir [duration of treatments to reactions onset not stated].The man, underwent endoscopic sinus surgery for silent sinus syndrome and recovered with improvement of his headache events. Owing to his avascular necrosis, he was admitted and underwent shoulder replacement surgery. He was found to be stable on beclometasone [beclomethasone] and efavirenz as alternative anti-retroviral medication for allergic rhinitis with no additional adverse effects.