Abstract:The objective of present research is to evaluate the lipid lowering efficacy and safety of switching within non-nucleoside reverse transcriptase inhibitors (NNRTI) in HIV-infected patients. This is a multicenter, retrospective study utilizing a comprehensive electronic patient registry to identify all adult HIV-infected patients seen from October 1, 1998 through October 1, 2006, who substituted efavirenz for nevirapine (EFV→NVP) or vice-versa (NVP→EFV), without change in other antiretrovirals. Lipid profiles before and after the switch were analyzed. A total of 124 patients were identified with 14 male (EFV→NVP, n = 9; NVP→EFV, n = 5) patients meeting the strict criteria for inclusion. An EFV→NVP switch resulted in significant reductions in TC -16% and non-HDL -25% (p≤0.02) and a trend towards a reduction in LDL-C -12%, TG -27%, TC/HDL -23%, TG/HDL -48% and an increase in HDL-C +15% without any changes to BMI, viral or immunological control. However, a NVP→EFV switch appeared to result in a non-significant worsening of LDL-C +29%, HDL-C -8%, TG +36%, non-HDL +28%, TC/HDL +57% and TG/HDL +46%. Lastly, more patients achieved their lipid goals when switched from EFV to NVP. These data suggest that switching from EFV to NVP-based HAART is associated with lipid improvement, however, switching from NVP to EFV-based HAART is associated with worsening of serum lipids.