Antiretroviral drugs, Lopinavir

Due to first-pass metabolism, if administered alone lopinavir has varied plasma levels. This problem is overcome by adding ritonavir to the formulation. Its oral absorption is rapid, and its bioavailability is increased by food rich in fat content. Lopinavir is metabolized by cytochrome P-450 isoenzyme CYP3A4. Most of the drug in the plasma is bound to ai-acid glycoprotein. In combination with other antiretroviral agents, lopinavir is indicated for the treatment of HIV infection. 

Zidovudine The differential effects of antiretroviral drugs on body fat disposition have been studied in 50 HTV-1 infected men in a randomized single-blind comparison of zidovudine + lamivudine with lopinavir + ritonavir and nevirapine with lopinavir + ritonavir [67 ]. In those who took the zidovudine-based therapy limb fat fell progressively from 3 months onward by a mean of 684 g up to 24 months, whereas abdominal fat increased, but exclusively in the visceral compartment. In contrast, in those who took nevirapine-based therapy there was a generalized increase in fat mass. After 24 months there were no significant differences in HDL cholesterol and the total/HDL cholesterol ratio, but total and low density lipoprotein (LDL) cholesterol were higher in those who had taken nevirapine. 

In a comparison of changes in bone mineral density in 106 HIV-1 infected, antiretroviral drug-naive patients, who were randomized to zidovudine -i- lamivudine with either efavirenz n = 32) or lopinavir + ritonavir n = 74) for 96 weeks, the mean changes from baseline in total bone mineral density were -2.5% (lopinavir -I- ritonavir) and -2.3% (efavirenz) [79 . The authors concluded that loss of bone mineral density during antiretroviral drug therapy is independent of the drug regimen. 

Atazanavir is an antiretroviral agent approved for use in combination with other antiretroviral agents for the treatment of HIV infections. Atazanavir is a peptidomimetic transition-state inhibitor that targets HIV-1 protease and reduces the viral replication and, thus, the virulence of HIV-1. Similar to saquinavir, ritonavir, indinavir, nelfinavir, amprenavir, and lopinavir, the drug is used in combination with RT inhibitors to produce excellent efficacy in patients with AIDS. 

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