From Concept to Care: Pharmacokinetic Boosting of Protease Inhibitors

protease inhibitors have played an instrumental role in decreasing mortality and morbidity among people with hiv infection. At the same time, this class of antiretrovirals has been associated with a number of disadvantages. First, protease inhibitor therapy often comes with a high pill burden, complex dosing schedules, and careful dietary considerations. Second, they are associated with a growing number of shortand long-term side effects, including a variety of metabolic complications. Third, cross-resistance remains a central concern; a simple switch from one protease inhibitor to another—if protease mutations are documented—often yields lackluster results. Fortunately, extensive data generated over the past several years have shed more encouraging light on the utility of protease inhibitors in the treatment of hiv infection. Pharmacokinetic “boosting”—primarily the use of ritonavir (Norvir) to boost concentrations of other protease inhibitors—has, in effect, rendered many of these drugs easier to take and more effective. Research is also emerging with respect to the use of two protease inhibitors—both boosted using low-dose ritonavir—as a therapeutic option. These double-boosted protease inhibitor combinations appear to hold a great deal of promise, particularly for patients who have tried and failed protease inhibitor therapy in the past.