<prompt> Raltegravir belongs toNIsNNIsIsCCR5 antagonist  <response>: More than 25 antiretrovirals ARV drugs in six mechanistic classes are Food and Drug Administration FDA-approved for treatment of HIV infection. These six classes include the nucleosidenucleotide reverse transcriptase inhibitors NIs, non-nucleoside reverse transcriptase inhibitors NNIs, protease inhibitors PIs, a fusion inhibitor FI, a CCR5 antagonist, and integrase strand transfer inhibitors Is. In addition, two drugs, ritonavir V or r and cobicistat COBI or c are used solely as pharmacokinetic PK enhancers or boosters to improve the pharmacokinetic profiles of some ARV drugs e.g., PIs and the I elvitegravir .Dolutegravir , Elvitegravir , Raltegravir are integrase strand transfer inhibitors Is. 