Isentress (Raltegravir) + Sustiva (Efavirenz)

Isentress and Sustiva are antiretroviral medications that can be combined or used simultaneously. So far, no interaction has been found between these two drugs.

What Is Isentress Used For?

Isentress is a relatively popular antiretroviral medication that is used for treating HIV infection in children and adults alike. Its main purpose is to prevent the virus from multiplying and progressing. Subsequently, a patient’s viral load will reduce and may become undetectable. One popular misconception is that Isentress can cure HIV. This is highly incorrect. Isentress does not cure or eliminate this infection. Rather, it inhibits the action of the virus in the human body, thereby protecting and boosting the patient’s immune system.

The active ingredient in Isentress is raltegravir, which is responsible for the drug’s action. The med should not be taken without prior consultation with a certified doctor. In the same vein, it is suitable only for adults and children who weigh at least 2 kilograms [1]. Patients who are allergic to raltegravir should stay away from Isentress and consult their doctor for suitable alternatives.

What Is Sustiva Used For?

Sustiva is another antiretroviral medication normally used with other ARV drugs to stop HIV from multiplying in the body [2]. Its active component is efavirenz, which is a highly potent substance.

Sustiva is a very sensitive medication and as such should not be taken without a doctor’s approval. Pregnant women should equally avoid using this medication as it could negatively affect their unborn child.

Although Sustiva is quite effective in treating HIV, it does not prevent transmitting the virus from a patient to his/her partner. As such, users of this medication should continue to practice safe sex.

This drug is only suitable for adults and children who are at least 3 months old.

How Do Isentress and Sustiva Interact with Each Other?

There are no known dangerous interactions for these two medications. However, clinical studies have shown that when combined with efavirenz, there could be a reduction in the plasma concentration of raltegravir [3]. However, this reduction is not clinically relevant and as such does not call for any adjustments in the prescribed dosage. So, in a nutshell, Isentress and Sustiva can be combined.


  1. Raltegravir.
  2. NCI Drug Dictionary.
  3. Minimal effects of ritonavir and efavirenz on the pharmacokinetics of raltegravir. Iwamoto M, Wenning LA, Petry AS, et al. Antimicrob Agents Chemother, 2008, 52(12): 4338-4343.
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