HIV Non Occupational Post-Exposure Prophylaxis (PEP)

Inclusion Criteria: * HIV uninfected on the basis of a negative HIV Rapid Test, EIA or Western blot, and a negative HIV-1 RNA assay * Possible non-occupational exposure to HIV-1, recent enough to permit receiving the first dose of study medication within 72 hours from the end of the exposure. * Able to understand the study procedures and willing to sign informed consent Exclusion Criteria: * Any active psychiatric illness or active drug or alcohol abuse that, in the opinion of the investigator, could prevent compliance with study procedures. * Pregnancy. * Chronic hepatitis B infection, diagnosed by either positive serum HBsAg or positive serum HBV DNA; or prior lamivudine therapy for hepatitis B. * Creatinine clearance less than 50 mL/min as calculated by Cockcroft-Gault formula. * Unwillingness to participate in study procedures, including Mental Health referral and intervention. * Known intolerance or allergy to tenofovir DF, emtricitabine or raltegravir. * Use of prohibited concomitant medication: dilantin, phenobarbital and rifampin which cannot be used with raltegravir.