Abacavir Pharmacokinetic Study in the Absence/Presence of Darunavir/Ritonavir or Raltegravir in HIV-infected Subjects

The study is being conducted as we have found that many patients with Human Immunodeficiency Disease (HIV) require a combination of different drugs to treat the HIV infection. Before using different combination of drugs, it is important to do studies to see if the drugs will affect the activity of one another. The study aims to help us understand if darunavir/ritonavir or raltegravir have any effects on levels of abacavir in the blood. The purpose of the study is to assess the pharmacokinetics (how a drug is absorbed, distributed and eliminated from your body) of abacavir in the absence and in the presence of darunavir/ritonavir and raltegravir.