Drug interactions between Fortovase and Reyataz
Results for the following 2 drugs: |
|
|---|---|
| Fortovase (saquinavir) | |
| Reyataz (atazanavir) | |
Interactions between your selected drugs
saquinavir ⇔ atazanavir
Applies to: Fortovase (saquinavir) and Reyataz (atazanavir)
ADJUST DOSE: Coadministration with atazanavir may significantly increase the plasma concentrations of saquinavir. The mechanism is atazanavir inhibition of CYP450 3A4, the isoenzyme responsible for the metabolic clearance of saquinavir. In 7 study subjects, atazanavir (400 mg once a day for 7 days) increased the mean steady-state peak plasma concentration (Cmax), area under the concentration-time curve (AUC) and trough plasma concentration (Cmin) of saquinavir from the soft gelatin capsule (SGC 1200 mg once a day) by 339%, 449% and 586%, respectively, compared to administration of saquinavir SGC alone. Administration of atazanavir and saquinavir SGC at 1200 mg once a day resulted in daily saquinavir systemic exposures similar to those observed with standard therapeutic dosing of saquinavir SGC alone at 1200 mg three times a day. However, the Cmax is about 79% higher. The interaction has also been studied with saquinavir mesylate (hard gelatin capsule, or HGC) in a ritonavir-boosted regimen. In 18 HIV patients, coadministration of atazanavir (300 mg once a day) and saquinavir HGC/ritonavir (1600 mg/100 mg once a day) resulted in a 42% increase in Cmax, a 60% increase in AUC, and a 112% increase in trough plasma concentration (Cmin) of saquinavir. Atazanavir pharmacokinetics were similar to those obtained in patients receiving atazanavir/ritonavir without saquinavir. No data are available for saquinavir HGC/ritonavir given in a dosage of 1000 mg/100 mg twice daily with atazanavir 300 mg once a day.
MANAGEMENT: Appropriate dosing recommendations for saquinavir or ritonavir-boosted saquinavir in combination with atazanavir have not been established. A regimen consisting of atazanavir 400 mg or 600 mg and saquinavir HGC 1200 mg given once daily in combination with two nucleoside reverse transcriptase inhibitors has been studied in antiretroviral-experienced patients and appears to be safe and as effective as ritonavir-boosted saquinavir given as 400 mg/400 mg twice daily with two NRTIs. However, data are limited.
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