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Other Names: Fuzeon®, T-20
Manufacturer: Roche - Trimeris Pharmaceuticals, Inc.

What is it?

Enfuvirtide is an investigational anti-HIV medication. It belongs to a new class of anti-HIV medications called ‘fusion inhibitors.’

How does it work?

Enfuvirtide prevents HIV from entering a cell and using the cell to make more HIV. Specifically, it prevents the HIV particle from binding to the outer membrane of the immune cell. If HIV cannot bind to the immune cell, it cannot enter that cell and use that cell to make more HIV particles.

How do I take it?

Enfuvirtide is available as a white powder in a single dose vial. You will need to add sterile water taken from a different vial to the enfuvirtide powder. Enfuvirtide is injected just under the skin (subcutaneous) of the thigh, stomach, or upper arm. You will watch a video about how to prepare and inject the study medication. Also, you will prepare and administer the first dose with your study clinician.

  • Each vial of enfuvirtide contains 106 mg and will be reconstituted with 1.1 mL of sterile water. The administered dose is 90 mg (1 mL of fluid).
  • Once the drug has been diluted with water, it must be used within 2 to 5 minutes. If you mix your two daily doses at one time the second vial can be stored in the refrigerator for up to 24 hours.
  • Discard the vial and any remaining liquid after you have drawn up and injected the dose of enfuvirtide . Do NOT save any remaining liquid in the vial.

It is extremely important that you use enfuvirtide 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. For enfuvirtide, each dose should be taken every 12 hours (+/- 4 hours). If you forget a dose, take it as soon as you remember, but then wait at least 8 hours before taking the next dose. Contact your study clinician if you are not sure when to take your next dose. Do not stop taking the medication for any reason at any time unless you are directed to do so by your study clinician. If you are unable to continue taking your medication due to side effects, you should contact your provider immediately.

Special Considerations

  • Enfuvirtide should be stored at room temperature in a dry place, out of the reach of children.
  • Please bring your study medications (empty and partially used) to each study visit.


Some drugs taken together may have interactions that cause illness or impair the effectiveness of the drugs. It is a good idea to always check with your study clinician before taking any other medications, prescription or otherwise, to be sure it will not interact.

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 study clinician regularly for checkups so that side effects can be detected early and treated.

The most common side effects associated with enfuvirtide are injection site reactions (pain, swelling, redness), headache, fever, and rash.

Other possible side effects include abnormal liver function tests, and changes in blood cell counts. These side effects can be detected through regular laboratory monitoring.

It is important to report any side effects to your study clinician. Also, because you are also starting new antiretroviral medications, you may experience side effects related to those medications as well.


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