TMC125 is from the class of drugs called non-nucleoside reverse transcriptase inhibitors (NNRTIs). NNRTIs work by blocking reverse transcriptase, a protein that HIV needs to make more copies of itself. TMC125 is used in the treatment of adults with HIV-1 infection. The purpose of this trial is to see if there is any potential interaction (change in the effectiveness of the drug) when taking multiple-dose TMC125 and buprenorphine/naloxone together. The trial will also assess the short-term safety and tolerability (how well your body handles the drug) when TMC125 and buprenorphine/naloxone are taken together.