January 13, 2012 Raltegravir (Isentress) is a drug used for
antiviral therapy against HIV. It was formerly known as MK-0518.
It is manufactured by Merck. Raltegravir is the first "integrase
inhibitor" drug. When HIV infects a cell, it combines its
genetic code into the cell's own code. This is shown in Fact
Sheet 106, step 5. Raltegravir blocks this process. When
raltegravir blocks integration, HIV infects a cell but cannot
make more copies of itself. Raltegravir was approved in 2007 as
an antiretroviral drug against HIV as part of an antiretroviral
regimen. It was studied first in adults who had used
antiretroviral therapy for some time whose virus had already
developed resistance (see Fact Sheet 126) to existing
antiretroviral drugs. Late in 2008 it was approved for use in
patients just starting antiretroviral therapy. Raltegravir has
not been studied in children, pregnant women or older adults.
There are no absolute rules about when to start antiretroviral
drugs. You and your health care provider should co