Answer
Ritonavir strongly inhibits CYP3A4, which metabolises fluticasone propionate, and can increase intranasal fluticasone propionate plasma concentrations several hundredfold, markedly reducing cortisol and increasing the risk of systemic effects such as Cushing's syndrome and adrenal suppression.
Sources for this answer
- Flixonase Aqueous Nasal SprayGlaxoSmithKline UK · emc · SmPC §4.5 Interaction with other medicinal products · Version 24Document updated
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