This information is for people who have HIV infection. It tells you about combination treatments including enfuvirtide, a drug used for HIV infection. It is based on the best and most up-to-date research.
Does it work?
We don't know. There hasn't been enough good-quality research to be sure. Enfuvirtide is only used when other treatments no longer work (the virus has become resistant to them) or if you can't take other treatments because of side effects.
What is it?
Enfuvirtide is a newer type of drug to treat HIV infection. It's sometimes known as T-20 and its brand name is Fuzeon. It's a type of drug called a fusion inhibitor. It works by stopping HIV getting inside your cells.
It's used in combination with other antiretroviral drugs. You take it as an injection twice a day.
How can it help?
We don't know for sure how enfuvirtide can help. There haven't been any of the best type of studies (double-blind randomised controlled trials).
The research so far suggests it may help improve CD4 count and reduce viral load for people whose other treatments are no longer working.  CD4 cells are part of your immune system, and how many you have (your CD4 count) is a sign of how healthy your immune system is. Your viral load is how much HIV is in your blood.
How does it work?
Fusion inhibitors are designed to stop HIV sticking to your CD4 cells. This should stop the virus's DNA getting inside the cells.
If the drugs can prevent HIV from getting into your cells, then the virus will be unable to reproduce and kill the cells. Your viral load should go down and your CD4 count should go up.
Can it be harmful?
Yes, like all antiretroviral drugs, enfuvirtide has side effects. These include: 
Soreness and redness where you inject the drug (this happens to most people)
Losing your appetite and losing weight
Damage to nerve endings
Changes to your mood, such as feeling irritable and finding it hard to concentrate
Dry skin and acne.
Rarely, people get more serious symptoms, which show that the body is over-reacting to the drug. These are called hypersensitivity reactions. Signs of a hypersensitivity reaction include:
Your doctor should tell you which signs to watch out for. If you get them, you need to stop taking the medicine and see your doctor quickly.
How good is the research on combination treatments including enfuvirtide?
We didn't find any good-quality studies (double-blind randomised controlled trials) looking at combination treatments including enfuvirtide.
Your immune system is made up of the parts of your body that fight infection. When bacteria or viruses get into your body, it's your immune system that kills them. Antibodies and white blood cells are part of your immune system. They travel in your blood and attack bacteria, viruses and other things that could damage your body.
randomised controlled trials
Randomised controlled trials are medical studies designed to test whether a treatment works. Patients are split into groups. One group is given the treatment being tested (for example, an antidepressant drug) while another group (called the comparison or control group) is given an alternative treatment. This could be a different type of drug or a dummy treatment (a placebo). Researchers then compare the effects of the different treatments.
For more terms related to HIV infection
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