Fig. 2.

Levonorgestrel concentrations rebound after stopping efavirenz among two HIV-infected levonorgestrel implant users who switched to a nonefavirenz-based antiretroviral therapy regimen.

Legend: Levonorgestrel concentrations for two users undergoing switching to a nonefavirenz-based antiretroviral therapy regimen after having received the implant are plotted over time. Color-coded arrows correspond to the first study visit occurring after the switch from efavirenz. In both instances, serum levonorgestrel concentrations rebound above baseline concentrations.