Heart disease and high blood pressure are major health concerns for people with HIV. Standard treatment for these illnesses often includes calcium channel blockers (CCBs). There is a potential for significant drug interactions between CCBs and HIV protease inhibitors (PIs) that may influence the dosing, monitoring, and choosing of CCBs and PIs when used in people infected with HIV. This study will examine the drug interactions between 2 commonly used CCBs and the PI combination indinavir and ritonavir (IDV/RTV). This information should help doctors choose the appropriate treatment for high blood pressure or heart disease in people taking PIs.