Drug interactions between Norvir and Reyataz
Results for the following 2 drugs: |
|
|---|---|
| Norvir (ritonavir) | |
| Reyataz (atazanavir) | |
Interactions between your selected drugs
ritonavir ⇔ atazanavir
Applies to: Norvir (ritonavir) and Reyataz (atazanavir)
ADJUST DOSE: Coadministration with ritonavir may significantly increase the plasma concentrations of atazanavir. The mechanism is ritonavir inhibition of CYP450 3A4, the isoenzyme responsible for the metabolic clearance of atazanavir. In 28 study subjects, ritonavir (100 mg once a day for 10 days) increased the mean steady-state peak plasma concentration (Cmax), area under the concentration-time curve (AUC) and trough plasma concentration (Cmin) of atazanavir (300 mg once a day) by 86%, 238% and over 1000%, respectively, compared to administration of atazanavir alone. Compared with historical data from standard therapeutic dosing of atazanavir alone at 400 mg once a day, administration of atazanavir/ritonavir at 300 mg/100 mg once a day increased atazanavir mean Cmax, AUC and Cmin by 18%, 103% and 671%, respectively.
MANAGEMENT: Coadministration of atazanavir and ritonavir is currently under clinical investigation. Patients requiring the combination should be prescribed atazanavir 300 mg with ritonavir 100 mg as a single daily dose with food.
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