• To evaluate virologic control with a 5 day on, 2 day off schedule
  

• To evaluate change in CD4+ T-cell counts in both arms
  
• To evaluate quality of life in both arms
  
• To evaluate antiretroviral toxicity in both arms
  
• To evaluate change in viral resistance patterns in both arms
  
• To evaluate levels of efavirenz in the blood in both arms
  
• To evaluate adherence in both arms
  

The purpose of this study is to evaluate virologic control of a weekly schedule of 5 days of treatment followed by two days off treatment versus continuous treatment with the same regimen. This is a larger study based on the results of our successful pilot study using the same protocol. The 48 week, phase IV trial addresses the issues of the high cost of HIV treatment, adherence problems associated with daily treatment, and cumulative toxicities. Virologic and immunologic parameters, drug levels of efavirenz, adherence, and toxicity will be measured. Subjects will have to be seen at CRI for 6 visits after randomization. Subjects randomized to daily therapy will cross over to 5/2 therapy at 24 weeks if their viral load remains undetectable.

Inclusion Criteria:

• Age 18 years or older
• CD4 count > or = 200
• Viral load < 50
• Treatment with a regimen containing efavirenz and tenofovir and lamivudine or emtricitabine for at least 90 days prior to screening

Exclusion Criteria:

• Detectable HIV RNA on an ultrasensitive assay within the 90 days preceding screening
• Prior evidence of intermediate or high level resistance to efavirenz, tenofovir or cytidine analogues
• Hepatitis B infection