 Raltegravir RAL is a recently FDA approved antiretroviral agent that inhibits HIV replication by blocking the integration of HIV proviral DNA into the host cell chromosomal DNA. RAL does not exhibit cross resistance to other ARV classes and thus has been initially used in HIV-infected individuals that are infected with drug resistant HIV strains. Recently published data on the use of RAL2,3in HIV-infected subjects with known ARV drug resistance or those without ARV drug resistance4 demonstrates that RAL is a potent agent, suppressing HIV viral loads in the majority of subjects and having excellent CD4 cell responses.2-4 RAL is metabolized through glucuronidation by the uridine diphosphate-glucuronosyl transferase 1A1 UGT1A1 enzyme pathway.5ATV is a known inhibitor of this enzyme pathway. ATV will increase RAL levels,5 however, the current DHHS HIV treatment guidelines do not recommend a change in the dose of RAL if given with ATV as persons receiving ATV and RAL have demonstrated good tolerability of the combination and low side effect profiles.1-3,5 