Drug interactions between Kaletra and Viracept
Results for the following 2 drugs: |
|
|---|---|
| Kaletra (lopinavir/ritonavir) | |
| Viracept (nelfinavir) | |
Interactions between your selected drugs
ritonavir ⇔ nelfinavir
Applies to: Kaletra (lopinavir/ritonavir) and Viracept (nelfinavir)
ADJUST DOSE: Coadministration with ritonavir may significantly increase the plasma concentrations of nelfinavir. The mechanism is ritonavir inhibition of CYP450 3A4 metabolism of nelfinavir. According to the nelfinavir product labeling, ritonavir (500 mg orally every 12 hours for 3 doses) increased the peak plasma concentration (Cmax) and area under the concentration-time curve (AUC) of nelfinavir (750 mg single dose) by 44% and 152%, respectively, in 10 subjects (HIV status not stated). In a study involving 18 healthy volunteers, simultaneous administration of ritonavir (400 mg single oral dose) decreased the clearance of nelfinavir (750 mg single dose) 2-fold compared to when nelfinavir was administered alone. Nelfinavir had negligible effect on the pharmacokinetics of ritonavir.
MANAGEMENT: Alteration in dosages or regimen is recommended by the manufacturer of nelfinavir during concomitant therapy with ritonavir. However, appropriate dosages for the combination, with respect to safety and efficacy, have not been established. Patients receiving the combination should be closely monitored for toxicity such as elevations in liver function tests and undue gastrointestinal disturbances, and the dosage(s) adjusted as necessary.
nelfinavir ⇔ lopinavir
Applies to: Viracept (nelfinavir) and Kaletra (lopinavir/ritonavir)
Coadministration with inhibitors of CYP450 3A4 may increase the plasma concentrations of lopinavir, which is metabolized by the isoenzyme. The magnitude and clinical significance of this interaction are unknown, particularly when in the presence of ritonavir as a pharmacokinetic booster. Limited data indicate that ketoconazole, a potent CYP450 3A4 inhibitor, does not substantially alter the plasma concentrations of lopinavir administered as lopinavir-ritonavir in a 4:1 ratio.
See also...
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