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Other Names: Isentress®

Manufacturer: Merck

What is it?

Raltegravir is an FDA approved antiretroviral medication, specifically, an integrase inhibitor. It is used to treat HIV, a retrovirus. Retroviruses use the genetic material in the body’s cells to produce more viruses, which can infect other cells.

How does it work?

Raltegravir is a new class of antiretroviral medication. It is designed to interfere with integrase, which is an enzyme necessary for HIV to successfully insert its viral DNA into a human host’s DNA. Specifically, raltegravir ties up the integrase enzymes and blocks the action of integrase which prevents the HIV from successfully inserting its DNA into the host DNA.

How do I take it?

  • Raltegravir is available as 400mg tablets .
  • The dose commonly given is 400mg twice daily.
  • Raltegravir can be taken with or without food.


It is extremely important that you take raltegravir and your other antiretroviral medications exactly as directed. You should set up a system that will help you remember to take your medicines so that you do not miss any doses. If you miss a dose, take it as soon as possible and space the remaining doses out over the rest of the day. However, if you skip a dose, do not take two doses at once. Do not stop taking the medication for any reason at any time unless you are directed to do so by your provider. If you are unable to continue taking your medication due to side effects, you should contact your provider immediately.

Special Considerations

  • Raltegravir should be stored at room temperature (77° F or 25° C) and out of reach of children.
  • Raltegravir is sensitive to moisture so it should be stored in a dry place.


Some drugs taken together may have interactions that cause illness or impair the effectiveness of the drugs. Since raltegravir is new, studies are being done to determine what interactions there might be with other medications. It is a good idea to always check with your provider before taking any other medications, prescription or otherwise, to be sure it will not interact with raltegravir.

There are limited data available regarding interaction with raltegravir . To date, raltegravir has been show to interact with following medications; atazanavir (increases amount of raltegravir in the bloodstream), tenofovir (increases amount of raltegravir in the bloodstream), efavirenz (decreases amount of raltegravir in the bloodstream) and tipranavir (decreases amount of raltegravir in the bloodstream).

The following medications should not be given together with raltegravir:

  • phenytoin
  • rifampin
  • phenobarbital

Many other drugs may interact with raltegravir so you must tell your provider about all medications you are currently taking. This includes any medications that you may take on an ‘as needed’ basis, such as sleeping pills or pain medications and herbal or natural medicines.

The medications listed above may be known by other names. In addition, there are many other medications that may have a potential interaction with raltegravir. Please notify your provider of all medications you take, including other study medications and herbal medications.

Side Effects

Not everyone experiences side effects. When they do occur, they may be mild, moderate or severe. Some side effects cannot be felt by the patient but can be found through laboratory tests, so it is important to see your provider regularly for checkups so that side effects can be detected early and treated.

The most common side effects of raltegravir are headache, diarrhea, nausea and stomach pain.Other side effects that may occur include tiredness, dizziness and insomnia

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