Slide 40 of 76
Notes:
PI Boosting can be achieved by adding ritonavir in a dose much lower than that used to treat HIV (i.e. ritonavir 100-400mg bid to boost vs 1200mg daily to treat)6. In other words, in this situation, ritonavir is used at small doses for the main purpose of inhibiting CYP450 activity; ritonavir is not being used for its own antiviral activity, and hence this approach is different compared to the “dual PI” strategy, where therapeutic levels of both PIs are achieved.
In general the effect of Ritonavir on other PI’s has been to increase Cmin and t1/2, with a variable effect on Cmax 2. Ritonavir itself has many side effects (hepatotoxicity, dyslipidemia, GI intolerance and multiple drug-drug interactions), so using lower doses may result in fewer hepatic and lipid abnormalities2.
