I et klinisk studie, hvor ritonavir 100 mg kapsler blev givet 2 gange daglig samtidig med 50 µg intranasal fluticasonpropionat (4 gange daglig) i 7 dage til raske personer, steg fluticasonpropionatplasmaniveauet signifikant, mens det interne kortisolniveau faldt med cirka 86% (90% konfidensinterval 82- 89%).
Fluticasone propionate (interaction with ritonavir): in a clinical study where ritonavir 100 mg capsules bid were co-administered with 50 µg intranasal fluticasone propionate (4 times daily) for 7 days in healthy subjects, the fluticasone propionate plasma levels increased significantly, whereas the intrinsic cortisol levels decreased by approximately 86% (90% confidence interval 82-89%).