Azelastineinteractions

No formal drug interaction studies have been performed with azelastine hydrochloride and fluticasone propionate nasal spray. The drug interactions of the combination are expected to reflect those of the individual components. Potent inhibitors of cytochrome P450 (CYP) 3A4: May increase blood levels of fluticasone propionate.

Ritonavir: Coadministration is not recommended. Other potent CYP3A4 inhibitors, such as ketoconazole: use caution with coadministration.

7.1 Central

Nervous System Depressants Concurrent use of azelastine hydrochloride and fluticasone propionate nasal spray with alcohol or other central nervous system depressants should be avoided because somnolence and impairment of central nervous system performance may occur.

7.2 Cytochrome P450 3A4

Ritonavir (a strong CYP3A4 inhibitor) significantly increased plasma fluticasone propionate exposure following administration of fluticasone propionate aqueous nasal spray, resulting in significantly reduced serum cortisol concentrations. During postmarketing use, there have been reports of clinically significant drug interactions in patients receiving fluticasone propionate and ritonavir, resulting in systemic corticosteroid effects including Cushing syndrome and adrenal suppression. Therefore, coadministration of fluticasone propionate and ritonavir is not recommended unless the potential benefit to the patient outweighs the risk of systemic corticosteroid side effects. Ketoconazole (also a strong CYP3A4 inhibitor), administered in multiple 200 mg doses to steady-state, increased plasma exposure of fluticasone propionate, reduced plasma cortisol AUC, but had no effect on urinary excretion of cortisol, following administration of a single 1,000 mcg dose of fluticasone propionate by oral inhalation route. Caution should be exercised when azelastine hydrochloride and fluticasone propionate nasal spray is coadministered with ketoconazole and other known strong CYP3A4 inhibitors.