title: Iatrogenic Cushing's syndrome and osteoporosis due to an interaction between fluticasone and ritonavir.
abstract: The advent of highly active antiretroviral therapy for HIV infection dramatically changed the landscape of the disease. Ritonavir, a protease inhibitor (PI) frequently used in low doses to 'boost' the concentrations of other PIs, inhibits the cytochrome P450 3A4 isoenzyme, a common metabolic pathway to multiple drugs, so the potential for drug interactions is not negligible. A 39-year-old man with HIV-1 infection, treated with a ritonavir-boosted PI, was started on fluticasone/salmeterol inhaler and intranasal fluticasone, in 2009, in the setting of asthma and allergic rhinitis. In 2013, he presented with 1-year evolution of symptoms suggesting Cushing's syndrome, and was experiencing recurrent falls. A spine CT showed a vertical L3 fracture and thoracolumbar erosions; a bone density scan revealed severe osteoporosis. Hormonal assays were compatible with hypothalamic-pituitary-adrenal axis suppression, and iatrogenic Cushing's syndrome due to ritonavir-fluticasone interaction was considered. Fluticasone was suspended and oral corticosteroid replacement initiated, with a favourable outcome.
authors.affiliation: Department of Internal Medicine, Centro Hospitalar Lisboa Central EPE, Lisboa, Portugal.
authors.forename: Luísa
authors.initials: L
authors.lastname: Azevedo
authors.affiliation: Department of Internal Medicine, Centro Hospitalar Lisboa Central EPE, Lisboa, Portugal.
authors.forename: Hugo
authors.initials: H
authors.lastname: Pêgo
authors.affiliation: Department of Internal Medicine, Centro Hospitalar Lisboa Central EPE, Lisboa, Portugal.
authors.forename: Teresa
authors.initials: T
authors.lastname: Souto Moura
authors.affiliation: Department of Internal Medicine, Centro Hospitalar Lisboa Central EPE, Lisboa, Portugal.
authors.forename: Isabel
authors.initials: I
authors.lastname: Germano
mesh_terms: D000058:Accidental Falls; D000328:Adult; D018926:Anti-Allergic Agents / Q000009:adverse effects*; D001249:Asthma / Q000188:drug therapy; D001993:Bronchodilator Agents / Q000009:adverse effects*; D003480:Cushing Syndrome / Q000139:chemically induced* / Q000188:drug therapy; D004347:Drug Interactions; D000068298:Fluticasone / Q000009:adverse effects*; D015658:HIV Infections / Q000188:drug therapy; D017320:HIV Protease Inhibitors / Q000009:adverse effects*; D006801:Humans; D007049:Iatrogenic Disease; D008297:Male; D010024:Osteoporosis / Q000139:chemically induced* / Q000188:drug therapy; D065631:Rhinitis, Allergic / Q000188:drug therapy; D019438:Ritonavir / Q000009:adverse effects*
chemical_list: D018926:Anti-Allergic Agents; D001993:Bronchodilator Agents; D017320:HIV Protease Inhibitors; D000068298:Fluticasone; D019438:Ritonavir