Raltegravir is an antiretrovial drug from the relatively new integrase inhibitor class. 

Integrase inhibitors target an enzyme called integrase which HIV uses to integrate its genetic code into human cells. Because this is a different point of action to that targeted by other drug classes, there is a good chance that people who have failed several prior treatment regimens will benefit from this drug, especially if it is combined with an optimised background regimen.

Basic info

Generic name raltegravir
Brand name Isentress
Also known as MK-0518 (former code name)
Drug class Integrase Inhibitors
Pediatric dosing? Available in doses suitable for children and/or young people.
Availability in Australia Available on the Pharmaceutical Benefits Scheme (PBS) through S100 prescribers since 2008
A Special Assistance Scheme (SAS) is in operation for this drug.
This drug may be available through clinical trials in Australia.
You may be able to import this drug from overseas for your personal use.
Formulation 400mg tablet

Taking it

Like most anti-HIV drugs, raltegravir must be taken in combination with other drugs to be completely effective. Commonly, raltegravir is combined with one other nucleoside (NRTI) drug and either a protease inhibitor or non-nucleoside, although other combinations are sometimes used. Your doctor will advise you on the right combination of drugs to suit your circumstances.


The usual adult dose is one 400mg tablet, taken twice a day.

Regardless of what you read on this website or elsewhere, you should always take your medications according to your doctor's instructions. If you're unsure, speak to your doctor or pharmacist.

With or without food

raltegravir may be taken with or without food

Side effect

All drugs can produce side effects in some people. These may be mild, moderate or severe, so you should be aware of potential side effects before starting any drug, and speak to your doctor if you experience side effects that concern you.

  • Common side effects may include nausea (upset stomach, feeling sick to the stomach), diarrhoea, headache.
  • Less common side effects may include fever, CPK elevation.
  • Rare side effects may include depression, abnormal liver function.
  • It's unlikely you will experience all of these side effects, and you may not experience any side effects at all. Before starting any new drug, ask your doctor about side effects you might experience and discuss strategies for dealing with side effects if they do occur. If you experience any significant side effect you should continue taking your medicine and see your doctor as soon as possible.

Interactions with other drugs

Raltegravir is broken down via a different method than most drugs, and so there are very few serious interactions with other anti-HIV drugs. Some evidence does exist that, when taken with tenofovir and ritonavir, levels of raltegravir in the blood may be reduced. When combined with atazanavir and ritonavir, blood levels of raltegravir may be increased.