Integrase inhibitors for HIV


Generic Name Brand Name
raltegravir Isentress

Raltegravir is available as pills. Usually, a pill is taken twice a day.

How It Works

Raltegravir blocks the HIV integrase enzyme. This prevents HIV from multiplying. When the amount of virus in the blood is kept at a minimum, the immune system has a chance to recover and grow stronger.

Why It Is Used

Raltegravir is used in combination with other antiretroviral medicines to treat HIV. It helps prevent the virus from spreading in the body and helps reduce the amount of virus in your blood (viral load). Raltegravir may be effective for people who have taken other anti-HIV drugs without success.

The use of three or more antiretroviral medicines (highly active antiretroviral therapy, or HAART) is the usual treatment for HIV infection.

The combination of medicines used for HAART will depend on your health, other conditions you might have (such as hepatitis), and results of testing. Talk to your doctor about the best treatment plan for you.

Treatment guidelines suggest the following for people with HIV:1, 2

  • When considering treatment, experts currently consider your CD4+ cell count and the presence or absence of symptoms more important than your viral load.
  • If your CD4+ cell count is below 350 cells per microliter (mcL), you should begin treatment to stabilize and increase your CD4+ cell count.
  • If your CD4+ cell count is more than 350 cells per microliter (mcL), treatment may be offered to help keep your immune system healthy and prevent AIDS.
  • If treatment is not started, your condition will be monitored with frequent CD4+ cell counts.
  • If you have symptoms of HIV or AIDS, doctors recommend starting treatment, whatever your CD4+ cell count is.
  • If you are pregnant, you should be treated to prevent your unborn baby (fetus) from becoming infected with HIV.
  • If you also have hepatitis B and are starting treatment for it, you should begin treatment for HIV as well.

How Well It Works

Raltegravir works well with other antiretroviral medicines to improve CD4+ cell counts and reduce viral load.3, 4

Side Effects

The most common side effects of raltegravir include diarrhea, nausea, headache, and fever.

See Drug Reference for a full list of side effects. (Drug Reference is not available in all systems.)

What To Think About

The U.S. Food and Drug Administration (FDA) approved raltegravir for people who have already been taking other anti-HIV medicines. It is not approved for use by people who are just starting drug treatment for HIV infection.

Raltegravir should be used to treat a pregnant woman only if the potential benefit is greater than the risk to the unborn baby (fetus).

Complete the new medication information form (PDF)(What is a PDF document?) to help you understand this medication.



  1. U.S. Department of Health and Human Services (2008). Guidelines for the use of antiretroviral agents in HIV-1-infected adults and adolescents. Available online:
  2. Hammer, Scott M, et al. (2008). Antiretroviral treatment of adult HIV infection: 2008 recommendations of the International AIDS Society USA Panel. JAMA, 300 (5): 555–570.
  3. Steigbigel RT, et al. (2008). Raltegravir with optimized background therapy for resistant HIV-1 infection. New England Journal of Medicine, 359(4): 339–354.
  4. Cooper DA, et al. (2008). Subgroup and resistance analyses of raltegravir for resistant HIV-1 infection. New England Journal of Medicine, 359(4): 355–365.

Last Updated: April 10, 2009

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