Slide 42 of 76
Notes:
It appears that ritonavir can have differential effects on the kinetic profile of different protease inhibitors.
- a) Cmax boosting: Saquinavir, nelfinavir and lopinavir are highly susceptible to P-gp degradation in the intestinal tract and/or first pass metabolism; thus the primary effect of ritonavir coadministration will be to enhance bioavailability. This allows for use of lower protease dosages.
- b) Half-life boosting: On the other hand, with amprenavir and indinavir, the primary effect of ritonavir is to decrease drug clearance and prolong half-life. This may allow for decreased dosing frequency.
It should be noted that the overall effect on protease inhibitor disposition is often a combination of these two mechanisms.
Hoetelmans RMV, Piscitelli SC, Hill AM. A Guide to Protease Inhibitor Boosting. Copyright F.Hoffmann-LaRoche, April 2001.
