Drug interactions between Invirase and Kaletra
Results for the following 2 drugs: |
|
|---|---|
| Invirase (saquinavir) | |
| Kaletra (lopinavir/ritonavir) | |
Interactions between your selected drugs
saquinavir ⇔ ritonavir
Applies to: Invirase (saquinavir) and Kaletra (lopinavir/ritonavir)
ADJUST DOSE: Coadministration with ritonavir (RTV) may significantly increase the bioavailability of saquinavir (SQV) from both the hard gelatin capsule (HGC) and soft gelatin capsule (SGC) formulations. The mechanism is RTV inhibition of CYP450 3A4 metabolism of SQV in the intestine and liver. In seven HIV+ patients stabilized on their antiretroviral regimen, addition of RTV (300 mg orally twice a day for 4 days) increased the median peak plasma concentration (Cmax) and 8-hour area under the concentration-time curve (AUC) of SQV (HGC 600 mg three times a day) by 30-fold and 58-fold, respectively, compared to baseline. In 57 healthy volunteers, escalating single doses of SQV (HGC) and RTV yielded comparable results, but increasing RTV dosages tended to produce less than proportional increases in SQV Cmax and AUC. The magnitude of the interaction is considerably less with the SGC formulation but still substantial. In individual groups of 8 healthy volunteers, various regimens of SQV (SGC 800 mg twice a day) and RTV (200 to 400 mg twice a day) for 14 days led to an approximate overall 9.6-fold increase in SQV Cmax and 20-fold increase in SQV AUC. RTV tended to reduce intersubject variability in SQV plasma levels. SQV had negligible effect on the pharmacokinetics of RTV.
MANAGEMENT: Based on the magnitude of interaction, SQV dosage should be reduced when coadministered with RTV. A regimen of (SQV HGC or SGC:RTV) 400:400 mg or 1000:100 mg twice daily is usually recommended based on their convenience and favorable safety-to-efficacy profile. Limited data suggest that dosages of 1200 to 2000:100 mg once daily may also be feasible and warrant further investigation. Patients receiving the combination should be closely monitored for toxicity including elevations in liver function tests and neutropenia.
saquinavir ⇔ lopinavir
Applies to: Invirase (saquinavir) and Kaletra (lopinavir/ritonavir)
ADJUST DOSE: Evidence from several clinical trials indicate that saquinavir plasma concentrations achieved with saquinavir 1000 mg in combination with lopinavir-ritonavir 400 mg-100 mg twice a day are similar to those observed following saquinavir/ritonavir 1000 mg/100 mg twice a day.
MANAGEMENT: The recommended dosage for saquinavir is 1000 mg twice daily when coadministered with lopinavir-ritonavir 400 mg-100 mg twice daily. Once-daily dosing of lopinavir-ritonavir has not been studied for use in combination with saquinavir.
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