Lack of enrollment

Data suggests that women taking drugs to treat human immunodeficiency virus (HIV) have higher amounts of drugs in their body compared with men taking the same dose of anti-HIV drugs. The reason for this higher drug exposure has not yet been determined. The primary purpose of this study is to examine whether a pharmacokinetics (factors that determine the amount of drug in the body) of anti-HIV drugs change during different phases of the menstrual cycle in women and ultimately result in higher amounts of drug in the body compared with men. In other words, we plan to examine whether changes in sex hormones throughout the menstrual cycle affect the amount of anti-HIV drugs in HIV infected women. The antiretroviral drugs atazanavir, ritonavir, tenofovir and emtricitabine will be studied.

Inclusion Criteria:

• HIV positive females between 21-40 years of age.
• Subjects must be receiving anti-HIV regimen consisting of tenofovir, emtricitabine, atazanavir, and ritonavir for a minimum of 4 weeks prior to the study.
• Subjects must have regular menstrual cycle (period), define at least 10 cycles a year, occurring approximately every 28 days+/- 4 days and cycle length varying by not more than 7 days.

Exclusion Criteria:

• Subjects can not be breast feeding, pregnant, or taking oral contraceptives (birth control pills) for at least 3 months prior to the study.
• Subjects may not have the intrauterine device (IUD), Mirena, in place to prevent pregnancy.

HIV-infected women will be selected from the primary care office