Ritonavir - An effective drug against HIV

Abstract

The new HIV protease inhibitors are likely to represent a major advance in the treatment of HIV infection, particularly when used in combination with other antiretroviral agents. The addition of ritonavir to the standard drug regimen of patients with HIV infection has resulted in decreased mortality and has been shown to slow down the clinical progression of disease as compared to placebo recipients. Although the drug was well tolerated and was not associated with any serious adverse reaction, data from long-term trials is eagerly awaited to corroborate the safety of ritonavir. The problem with other anti-retroviral agents is the emergence of resistance, which is responsible for their waning efficacy. Although resistance has been seen with ritonavir, it arises as a result of multiple mutations, which produces a stepwise increment in resistance. This very complex pattern of resistance explains the absence of rapid appearance of resistant mutants with ritonavir. Moreover, the resistance between ritonavir and saquinavir is not over-lapping, and therefore the combination of these drugs is an attractive proposition especially as ritonavir improves the bioavailability of saquinavir. As such, ritonavir may become an important component of the combination regimen to treat advanced as well as less advanced HIV infection.